VMware: improve connection issue diagnostic

This exception block can swallow all issues with a connection
adding something to log the exception thrown can aid in
the troubelshooting of a Nova node's configuration. This is
invaluable when guiding someone in the field through setup
because they may mis-type a key value or misconfigure an IP.

Change-Id: I27e5ed5c51926cfeb6747980df02a396f566dd77
Merge "VMware: improve connection issue diagnostic"