Changed newFromServiceCatalog to return the first endpoint if the DEFAULT is not found

If the default region is not found and a user has not explicitly specified a region, return the first usable endpoint. This change allows the library to be used on private and other public clouds without specifying the region. Third party application support for specifying a region is a bit hit and miss, and often times a service catalog only has a single region in which case explicitly specifying a region is not always remembered.