ConfigurationManagerImpl: Fix NPE when trying to access method on null object

Before checking obj.length, the fix is to check that the obj is not null

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>
NetUtils: Check for NPE in getDefaultHostIp method when processing nic/mac

On hosts or containers where they don't have valid mac address on nic resulting
in null, NetUtils.getNetworkParam can throw NPE.

This was a case found on TravisCI where OpenVZ containers are used. This method
(getDefaultHostIp) is used at several other places within the ACS codebase to
get the host IP and if null is caught we fallback to localhost or 127.0.0.1, so
we therefore set info to null before trying to process network param and if we
fail we return null and expect other layers to use localhost.

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>