Fixes Opt types in glance/notifier/notify_kombu.py

Changed rabbit_retry_backoff and rabbit_retry_max_backoff to IntOpt.

Fixes bug #1201697

Change-Id: Ia1a74b6bb2873e59677a7fea6652a6c006f38175
Merge "Fixes Opt types in glance/notifier/notify_kombu.py"