Modified install-openmano.sh to use pyvcloud version 18.2.2

Change-Id: I252a4635d7e7297115bf85f291d3e49482997949
Signed-off-by: kasar <pkasar@vmware.com>
diff --git a/scripts/python-osm-ro.postinst b/scripts/python-osm-ro.postinst
index b2a2ff2..01ce867 100755
--- a/scripts/python-osm-ro.postinst
+++ b/scripts/python-osm-ro.postinst
@@ -23,7 +23,7 @@
 
 #Pip packages required for vmware connector
 pip install --upgrade pip
-pip install --upgrade pyvcloud
+pip install --upgrade pyvcloud==18.2.2
 pip install --upgrade progressbar
 pip install --upgrade prettytable
 pip install --upgrade pyvmomi