Fix try/except syntax for Python 3

"except (IOError, errors):" fails with a TypeError if errors is a tuple on
Python 3, whereas it was accepted in Python 2.

Change-Id: I65cfb60af87e76fdf2d37043fb106adbd4586fb9
Fix duplicate topic messages for Qpid topology=2

Manually applied ef406a21782134aeefb944f74b3f1a47d6169318 from
oslo-incubator to get the fix required for bug 1257293.

Copying the original commit message from oslo-incubator below.

"""
When multiple RPC servers (consumers) are subscribed to the same RPC
topic, a single RPC request to that topic should be received by only
one of the consumers.  A bug in the QPID driver caused every consumer
to receive a copy of the RPC request.  This bug affects only Topology
version 2.  This patch will cause a single queue to be created for
each topic, and shared among all consumers of that topic.  This
results in each RPC request being received by only one consumer,
in turn across all the competing consumers.
"""

Change-Id: I76bfa5b48bad4a70fbf06b74f4cc8234af6610c2
Closes-bug: #1257293.
Fix test_notifier_logger for Python 3

 * Get the current line at runtime, don't hardcode the line number
 * Only strip last character of the filename if it ends with ".pyc"
   or ".pyo".  On Python 3, import automatically replaces .pyc and
   .pyo with .py.
 * Use threading.current_thread().ident to get the identifier of the
   current thread. The get_ident() function is available in thread
   module in Python 2, but in threading module in Python 3. And on
   Python 3, logging.thread symbol does not exist anymore.

Change-Id: I3f248bb860caafaf38eefcf440d36b9bebc8f05e
Fix spelling errors in comments

Change-Id: I9f7de85912c687d37661c3301b5898960082fc13
Merge "Fix try/except syntax for Python 3"
Merge "Fix test_notifier_logger for Python 3"
Merge "Fix spelling errors in comments"
Merge "Fix duplicate topic messages for Qpid topology=2"
Removes use of timeutils.set_time_override

The set_time_override function in timeutils was written as a
helper function to mock utcnow for unittests before 'mock' was
generally used. Now that we have mock and fixture, we no longer
need to use it.

Change-Id: I9a0727edab12ccd5f1e4eb4f5f62d588f5a0faee
Partial-Bug: #1266962