Allow default-branch in our projects.yaml checking

Some projects may not be created with a master branch and choose to use
a different default-branch value. There is support for this in jeepyb
and our gitea git repo management role but we don't allow it in linting.
Update our linting to accomodate projects making this change.

Change-Id: I57ef2c10d2c29142801ba134c8183bb0393771a8

tools/check_valid_gerrit_projects.py

@@ -34,7 +34,7 @@ def tempdir():
         shutil.rmtree(reqroot, ignore_errors=True)
 
 
-def check_repo(repo_path):
+def check_repo(repo_path, default_branch):
     found_errors = 0
 
     print("Checking git repo '%s':" % repo_path)
@@ -45,11 +45,11 @@ def check_repo(repo_path):
         print("  Remote branches:")
         for r in branches:
             print("    %s" % r)
-        if 'origin/master' in branches:
-            print("  Master branch exists.")
+        if 'origin/%s' % default_branch in branches:
+            print("  %s branch exists." % default_branch)
         else:
             found_errors += 1
-            print("  ERROR: No master branch exists")
+            print("  ERROR: No %s branch exists" % default_branch)
         if 'origin/stable' in branches:
             found_errors += 1
             print("  ERROR: A branch named 'stable' exists, this will"
@@ -160,7 +160,8 @@ def main():
 
     VALID_LABELS = ["acl-config", "description", "docimpact-group",
                     "groups", "homepage", "options", "project",
-                    "upstream", "use-storyboard", "cgit-alias"]
+                    "upstream", "use-storyboard", "cgit-alias",
+                    "default-branch"]
     VALID_SCHEMES = ['https://', 'http://', 'git://']
     DESCRIPTION_REQUIRED = ['openstack', 'openstack-infra', 'openstack-dev',
                             'stackforge']
@@ -215,15 +216,16 @@ def main():
         # but not git@
         upstream = p.get('upstream')
         if upstream:
+            default_branch = p.get('default-branch', 'master')
             openstack_repo = 'https://opendev.org/%s' % name
             try:
                 # Check to see if we have already imported the project into
                 # OpenStack, if so skip checking upstream.
-                check_repo(openstack_repo)
+                check_repo(openstack_repo, default_branch)
             except git.exc.GitCommandError:
                 # We haven't imported the repo yet, make sure upstream is
                 # valid.
-                found_errors += check_repo(upstream)
+                found_errors += check_repo(upstream, default_branch)
             for prefix in VALID_SCHEMES:
                 if upstream.startswith(prefix):
                     break