Restore branch conditional on tempest-full

This change partially reverts I5d34e5b983b720dc1913d00ccc1a16d81a040d49.
Since the branch conditional can be more effectively applied on the
job definition located in the tempest repo, there is no need to change
the original override.

Partial-bug: 1739829
Depends-on: I8e0aa11cd2d92d5d6f5e9147a407374948920e7f
Change-Id: Ibfbc925af6eb274ced53312301b1733136ba4455

zuul.d/zuul-legacy-project-templates.yaml

@@ -172,19 +172,14 @@
       jobs:
         - legacy-tempest-dsvm-neutron-full:
             branches: ^stable/(newton|ocata|pike)$
-        # NOTE(andreaf) Only run on master for now.
-        # The negative lookup is redudant but it's a
-        # reminder that we don't want the job running there.
-        - tempest-full:
-            branches: ^(?!driverfixes/)master$
+        - tempest-full
         - neutron-grenade:
             branches: ^(?!stable/newton).*$
     gate:
       jobs:
         - legacy-tempest-dsvm-neutron-full:
             branches: ^stable/(newton|ocata|pike)$
-        - tempest-full:
-            branches: ^(?!driverfixes/)master$
+        - tempest-full
         - neutron-grenade:
             branches: ^(?!stable/newton).*$
     experimental: