Pass JSON to host_dns_check, fix issue with curl of harvester

Change-Id: I5b4dc9870e9c64f5a6ed77db787b6da096689ab6
diff --git a/roles/create-vms/library/host_dns_check.py b/roles/create-vms/library/host_dns_check.py
index 20413ab..cbd39ae 100755
--- a/roles/create-vms/library/host_dns_check.py
+++ b/roles/create-vms/library/host_dns_check.py
@@ -65,7 +65,7 @@
     result["command_on_fail"] = {}
     result["command_on_fail"]["command"] = command_on_fail
     try:
-        cmd_out = subprocess.check_output(shlex.split(command_on_fail), shell=True, stderr=subprocess.STDOUT)
+        cmd_out = subprocess.check_output(shlex.split(command_on_fail), stderr=subprocess.STDOUT)
         result["command_on_fail"]["retcode"] = 0
         result["command_on_fail"]["out"] = cmd_out
     except subprocess.CalledProcessError as e: