Make pkgdb_sync more resilient by always calling SETUP_PACKAGE if master does not exist

This should make it recover in case there are any repos in a weird state (aka, no master branch).
This could for example happen if the package was created in pkgdb after pkgdb_sync ran, but before
genacls.pkgdb runs, because then gitolite will see it as a new repo, and create a totally blank repo.
Especially since pkgdb_sync will abort after the first error, it would then leave all later created
repos broken as well.

Calling setup_git_package in a repo without master branch has no ill effect:
- Running git init on a pre-initialized repo is a no-op (or at least doesn't destroy current git data)
- Since it doesn't have master, it didn't run the script, so adding the first commit and hooks etc are
  what we want the script to do

Signed-off-by: Patrick Uiterwijk <puiterwijk@redhat.com>

roles/distgit/templates/pkgdb_sync_git_branches.py

@@ -187,7 +187,7 @@ def branch_package(pkgname, branches):
 
     # Create the devel branch if necessary
     if not os.path.exists(
-            os.path.join(GIT_FOLDER, '%s.git' % pkgname)):
+            os.path.join(GIT_FOLDER, '%s.git/refs/heads/master' % pkgname)):
         _invoke(SETUP_PACKAGE, [pkgname])
         if 'master' in branches:
             branches.remove('master')  # SETUP_PACKAGE creates master