metadata.py: return info after fallback methods

If python3 git module is not installed, we fall back to some git
command to get info. A previous commit (b8d22ed6) accidently deleted
the return statement, causing errors like below.

  Exception: UnboundLocalError: local variable 'InvalidGitRepositoryError' referenced before assignment

(From OE-Core rev: cd8aedc408afa4f8589f79e4d85befc7cac76ac6)

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/utils/metadata.py

@@ -76,6 +76,7 @@ def git_rev_info(path):
             info['commit_count'] = int(subprocess.check_output(["git", "rev-list", "--count", "HEAD"], cwd=path).decode('utf-8').strip())
         except subprocess.CalledProcessError:
             pass
+        return info
     try:
         repo = Repo(path, search_parent_directories=True)
     except (InvalidGitRepositoryError, NoSuchPathError):