Accurate exception info in api layer for aggregate

Adjust log information for exceptions in api layer for aggregate
according to
https://wiki.openstack.org/wiki/LoggingStandards#INFO_log_level_is_for_Operators
the LOG.info was removed because nova api already reported error to operator

Change-Id: I89394407495cf2d346e1f532ada236a4364aab24
Fake driver: remove unused method get_disk_available_least

The method was only used by the libvirt driver and this was
replaced by a local one.

Change-Id: I6d92b071e9b74b8ba19d4157ee60fa9a1b3c74a7
Remove a not used function _get_ip_by_id

There is a not used function in floating_ips.py, Remove it
since no one use it.

Change-Id: I6a45c73d9e2a897fdc45f00e7363db204663cd3c
Be explicit about objects in _shutdown_instance()

This adds a docstring to _shutdown_instance() making it clear that
it takes an Instance object. Also, pass an object to the method
from the test.

Related to blueprint compute-manager-objects-juno

Change-Id: Ia80c82ca0f5d8a470bb8f01f1520a82748a4f877
add repr for event objects

When an event object gets dumped in a stack trace, because there
is no __repr__ of it, we don't get any details about what it was.
Add a __repr__ to all the event objects so that we can get this
information on a fail.

Change-Id: I9a62a4348871b748c53b7354ad1b821fe987127d
Fixes internal server error for add/remove tenant flavor access request

Fixes the internal server error (500) response when an add or remove tenant access
to a flavor is made without specifying the tenant. Note that only the V2 API code
change is required because the V3 API version is protected by the input validation.

Change-Id: I7c126920016c7004fa55efb89747e97838d62f4e
Closes-Bug: 1253014
Merge "Fixes internal server error for add/remove tenant flavor access request"
Merge "add repr for event objects"
Merge "Remove a not used function _get_ip_by_id"
Merge "Be explicit about objects in _shutdown_instance()"
Merge "Accurate exception info in api layer for aggregate"
Merge "Fake driver: remove unused method get_disk_available_least"