Modified install-openmano.sh to use pyvcloud version 18.2.2

Change-Id: I252a4635d7e7297115bf85f291d3e49482997949
Signed-off-by: kasar <pkasar@vmware.com>
diff --git a/requirements.txt b/requirements.txt
index 0d6c432..2bfca00 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -12,7 +12,7 @@
 python-glanceclient
 python-neutronclient
 python-cinderclient
-pyvcloud
+pyvcloud==18.2.2
 pyvmomi
 progressbar
 prettytable