Issue 3768 - Check (and fix, if needed) multilocale builds

mozharness/base/vcs/vcsbase.py

Index: mozharness/base/vcs/vcsbase.py
===================================================================
--- a/mozharness/base/vcs/vcsbase.py
+++ b/mozharness/base/vcs/vcsbase.py
@@ -69,16 +69,19 @@ class VCSMixin(object):
         if not vcs_class:
             self.error("Running vcs_checkout with kwargs %s" % str(kwargs))
             raise VCSException("No VCS set!")
         # need a better way to do this.
         if 'dest' not in kwargs:
             kwargs['dest'] = self.query_dest(kwargs)
         if 'vcs_share_base' not in kwargs:
             kwargs['vcs_share_base'] = c.get('%s_share_base' % vcs, c.get('vcs_share_base'))
+        # Tries to checkout 'tag' if 'revision' is not defined
+        if 'revision' not in kwargs:
+            kwargs['revision'] = kwargs.get('tag')
         vcs_obj = vcs_class(
             log_obj=self.log_obj,
             config=self.config,
             vcs_config=kwargs,
             script_obj=self,
         )
         return self.retry(
             self._get_revision,