Include the date in the log of the last mirroring attempt

Otherwise, we have the log of the last attempt but we do not know
when that attempt was.

Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr>

pagure/lib/git.py

@@ -3056,7 +3056,7 @@ def mirror_pull_project(session, project, debug=False):
 
     try:
         # Pull
-        logs = []
+        logs = ["Run from: %s" % datetime.datetime.utcnow().isoformat()]
         logs = _run_command(["clone", "--mirror", remote, "."], logs)
         logs = _run_command(["remote", "add", "local", lclrepopath], logs)