Merge pull request #123 from xcp-ng/agf-fileSR_fix_with_offline_hosts

Fix a crash with cleanup operation while a host is offline.

Author: Ythogtha

drivers/cleanup.py

@@ -3000,7 +3000,7 @@ def _checkSlaves(self, vdi):
                 raise AbortException("Aborting due to signal")
             try:
                 self._checkSlave(hostRef, vdi)
-            except util.CommandException:
+            except XenAPI.Failure:
                 if hostRef in onlineHosts:
                     raise