Bug 1068 fixed for auth_url in keystone

When we pass auth_url in nbi.cfg -> [authentication], the auth_url is used by password manager
but not by keystone http client. Need to pass auth_url to httpclient so that it uses auth_url
instead of https://keystone:5000 which is in service catalog of keystone.
Added http://keystone:5000/v3 to docker files.
Added regex validation for auth_url.

Change-Id: Ie3e144dd826e73a27c25f917cf54e64cf4c22207
Signed-off-by: K Sai Kiran <saikiran.k@tataelxsi.co.in>
diff --git a/Dockerfile.fromdeb b/Dockerfile.fromdeb
index 9c3e245..ec348cb 100644
--- a/Dockerfile.fromdeb
+++ b/Dockerfile.fromdeb
@@ -66,7 +66,7 @@
 # authentication
 ENV OSMNBI_AUTHENTICATION_BACKEND               internal
 #ENV OSMNBI_AUTHENTICATION_BACKEND               keystone
-#ENV OSMNBI_AUTHENTICATION_AUTH_URL              keystone
+#ENV OSMNBI_AUTHENTICATION_AUTH_URL              http://keystone:5000/v3
 #ENV OSMNBI_AUTHENTICATION_AUTH_PORT             5000
 #ENV OSMNBI_AUTHENTICATION_USER_DOMAIN_NAME      default
 #ENV OSMNBI_AUTHENTICATION_PROJECT_DOMAIN_NAME   default