Rackspace database resource output is null

Rackspace database resource output is null

This change is a small correction to my previous change that was
already merged(bug #1204601). Below given code snippets show the
one line code change
(Please note the change in return statement in below code)

code before this change:
        for link in dbinstance.links:
            if link['rel'] == 'self':
                return dbinstance.links[0]['href']

code with this change:
        for link in dbinstance.links:
            if link['rel'] == 'self':
                return link['href']

Fixes Bug #1204601

Change-Id: Ia81722eb3877e15e1c472e94ed845f3425949b68