Fix repository checking

Commit 77f980b70e broke the repository
checking code, and would throw an exception when trying to access an
invalid member 'key'.

Change-Id: Ic77d26c57647ad21fe78cdd3253290a42b231d7e

gertty/sync.py

@@ -609,7 +609,7 @@ class CheckReposTask(Task):
             try:
                 repo = app.getRepo(project.name)
                 if repo.newly_cloned or app.fetch_missing_refs:
-                    sync.submitTask(CheckRevisionsTask(key,
+                    sync.submitTask(CheckRevisionsTask(project.key,
                                                        priority=LOW_PRIORITY))
             except Exception:
                 self.log.exception("Exception checking repo %s" %