VOL-2241:  Python 3 migration

 - rename adapter class file and remove unneeded __init__ to make imports work without major rearrange
 - venv and Dockerfile fixups needed for new pyvoltha (cannot install old first)
 - clean up yaml config file as it contained empty entries that failed to parse
 - clean up imports
 - remove itervalues iter*
 - convert to list() as needed
 - test with python 3.6
 - skip non-dict items in tcont loop
 - update to voltha-protos 2.1.0
 - migrate socketserver and simplehttpserver to python3 import

Change-Id: Id8efa72b6796a3055b1927716503a33544bb6548
diff --git a/python/adapters/brcm_openomci_onu/probe.py b/python/adapters/brcm_openomci_onu/probe.py
index 6b4d39d..32646fd 100644
--- a/python/adapters/brcm_openomci_onu/probe.py
+++ b/python/adapters/brcm_openomci_onu/probe.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
-from SimpleHTTPServer import SimpleHTTPRequestHandler
+from http.server import SimpleHTTPRequestHandler
 from structlog import get_logger
 
 log = get_logger()