Create connection for each qpid notification.

Previously the qpid notifier created a connection to the qpid broker
when the notifier was initialized and reused that for each notification.
This is broken when API workers are used.  Instead, just create a new
connection on demand when a notification gets sent out.

Fix bug 1100317.

Change-Id: I7a17e5e4bd8efd771ff8cd0e1d04107a79789763
Merge "Create connection for each qpid notification."