use single ssh connection to onos
It belongs to VOL-4041 and is the second part.
Keyword 'Execute ONOS CLI Command on open connection' is deprecated
and is replaced by keyword
'Execute ONOS CLI Command use single connection' for all test suites
and libraries.

Change-Id: Ib5078b50d22e812e927e437a0e6f0e249f95ee9a
diff --git a/tests/scale/Voltha_Scale_Tests.robot b/tests/scale/Voltha_Scale_Tests.robot
index 1eb15f2..7107218 100755
--- a/tests/scale/Voltha_Scale_Tests.robot
+++ b/tests/scale/Voltha_Scale_Tests.robot
@@ -105,7 +105,7 @@
     [Tags]  activation  plot-onos-olts
     ${onos_devices}=    Compute Device IDs
     FOR     ${deviceId}     IN  @{onos_devices}
-        Wait for Olt in ONOS   ${onos_ssh_connection}  ${deviceId}
+        Wait for Olt in ONOS   ${${ONOS_SSH_IP}    ${ONOS_SSH_PORT}}  ${deviceId}
     END
 
 Onu Activation in VOLTHA
@@ -118,7 +118,7 @@
     [Tags]      activation    plot-onos-ports
     ${onos_devices}=    Compute Device IDs
     FOR     ${deviceId}     IN  @{onos_devices}
-        Wait for Ports in ONOS      ${onos_ssh_connection}  ${total_onus_per_olt}   ${deviceId}     BBSM
+        Wait for Ports in ONOS      ${${ONOS_SSH_IP}    ${ONOS_SSH_PORT}}  ${total_onus_per_olt}   ${deviceId}     BBSM
     END
 
 Flows validation in VOLTHA before subscriber provisioning
@@ -144,7 +144,7 @@
 
     ${onos_devices}=    Compute Device IDs
     FOR     ${deviceId}     IN  @{onos_devices}
-        Wait for all flows to in ADDED state    ${onos_ssh_connection}
+        Wait for all flows to in ADDED state    ${${ONOS_SSH_IP}    ${ONOS_SSH_PORT}}
         ...     ${deviceId}     ${workflow}    ${total_onus_per_olt}    1    false
         ...     ${withEapol}    ${withDhcp}     ${withIgmp}   ${withLLDP}
     END
@@ -155,7 +155,7 @@
 
     ${onos_devices}=    Compute Device IDs
     FOR     ${deviceId}     IN  @{onos_devices}
-        Wait for AAA Authentication     ${onos_ssh_connection}  ${total_onus_per_olt}   ${deviceId}
+        Wait for AAA Authentication     ${${ONOS_SSH_IP}    ${ONOS_SSH_PORT}}  ${total_onus_per_olt}   ${deviceId}
     END
 
 Provision subscribers
@@ -164,7 +164,7 @@
     Should Be Equal   ${enableSubscriberProvisioning}     true
     ${onos_devices}=    Compute Device IDs
     FOR     ${olt}  IN  @{onos_devices}
-        Provision all subscribers on device  ${onos_ssh_connection}     ${ONOS_SSH_IP}     ${ONOS_REST_PORT}  ${olt}
+        Provision all subscribers on device  ${${ONOS_SSH_IP}    ${ONOS_SSH_PORT}}    ${ONOS_SSH_IP}    ${ONOS_REST_PORT}  ${olt}
     END
 
 Flows validation in VOLTHA after subscriber provisioning
@@ -191,7 +191,7 @@
 
     ${onos_devices}=    Compute Device IDs
     FOR     ${deviceId}     IN  @{onos_devices}
-        Wait for all flows to in ADDED state    ${onos_ssh_connection}
+        Wait for all flows to in ADDED state    ${${ONOS_SSH_IP}    ${ONOS_SSH_PORT}}
         ...     ${deviceId}     ${workflow}    ${total_onus_per_olt}    1    true
         ...     ${withEapol}    ${withDhcp}     ${withIgmp}   ${withLLDP}
     END
@@ -201,7 +201,7 @@
     [Tags]      dhcp  plot-onos-dhcp
     ${onos_devices}=    Compute Device IDs
     FOR     ${deviceId}     IN  @{onos_devices}
-        Wait for DHCP Ack     ${onos_ssh_connection}  ${total_onus_per_olt}     ${workflow}     ${deviceId}
+        Wait for DHCP Ack     ${${ONOS_SSH_IP}    ${ONOS_SSH_PORT}}  ${total_onus_per_olt}     ${workflow}     ${deviceId}
     END
 
 Perform Igmp Join
@@ -224,7 +224,7 @@
     ${onos_devices}=    Compute Device IDs
     FOR     ${deviceId}     IN  @{onos_devices}
         Run Keyword And Continue On Failure    Wait Until Keyword Succeeds    ${timeout}    5s
-        ...    Verify ONUs in Group Count in ONOS    ${onos_ssh_connection}    ${total_onus_per_olt}    ${deviceId}
+        ...    Verify ONUs in Group Count in ONOS    ${${ONOS_SSH_IP}    ${ONOS_SSH_PORT}}    ${total_onus_per_olt}    ${deviceId}
     END
 
 Perform Igmp Leave
@@ -247,7 +247,7 @@
     ${onos_devices}=    Compute Device IDs
     FOR     ${deviceId}     IN  @{onos_devices}
         Run Keyword And Continue On Failure    Wait Until Keyword Succeeds    ${timeout}    5s
-        ...    Verify Empty Group in ONOS    ${onos_ssh_connection}    ${deviceId}
+        ...    Verify Empty Group in ONOS    ${${ONOS_SSH_IP}    ${ONOS_SSH_PORT}}    ${deviceId}
     END
 
 Disable and Delete devices
@@ -278,9 +278,6 @@
     Run Keyword If    '${workflow}'=='tt'
     ...    Send File To Onos    ${CURDIR}/../../tests/data/onos-igmp.json    apps/
 
-    ${onos_ssh_connection}    Open ONOS SSH Connection    ${ONOS_SSH_IP}    ${ONOS_SSH_PORT}
-    Set Suite Variable  ${onos_ssh_connection}
-
 Teardown Suite
    [Documentation]    Close the SSH connection to ONOS
     Close All ONOS SSH Connections