Remove the deprecated "giturl" option

From openstackdocstheme 1.18.0, valid Git URLs can be retrieved by
openstackdocstheme[1], we do not need giturl option anymore.

[1] https://review.openstack.org/532163

Change-Id: I579cebae6486d250915f936f0c1c61008471c089

api-ref/source/conf.py

@@ -76,12 +76,8 @@ version = __version__.rsplit('.', 1)[0]
 # The full version, including alpha/beta/rc tags.
 release = __version__
 
-# Config logABug feature
-giturl = u'https://git.openstack.org/cgit/openstack/swift/tree/api-ref/source'
-# source tree
 # html_context allows us to pass arbitrary values into the html template
 html_context = {'bug_tag': 'api-ref',
-                'giturl': giturl,
                 'bug_project': 'swift'}
 
 # The language for content autogenerated by Sphinx. Refer to documentation