glance-replicator: enable logging exceptions into log file

bug 1213779

Currently, glance-replicator provides option to enable logging
information into a specified file. But exceptions are not logged
into the log file when they are thrown.

Reproduce steps:

When setting a wrong source or target address, exceptions would be
thrown, but not logged into log file.

Change-Id: Ic2c59e04aa6099f3ede0c6b8579c31a3dfff895c
Merge "glance-replicator: enable logging exceptions into log file"