Convert to more modern openstack-common.conf format.

Change-Id: Ib02edb34b02d63f2dcf6fa08a224e5ec1fa02525
Only add logging handlers if there currently aren't any

This corrects an odd problem where Horizon would stand up multiple
client objects, which would cause duplicate/triplicate/dozens of
repeated log lines in its log files, due to multiple identical
handlers being added to the logging object

Fixes Bug 1182678

Change-Id: I1f3bae0a39f28412c99e5d04f4364611f2a5facb
Merge "Convert to more modern openstack-common.conf format."
Merge "Only add logging handlers if there currently aren't any"
Revert "Support force update quota"

This reverts commit e8b665edbfcd86488f75ed0b79dafdedbf8f5950.

The previous commit created an incompatibility in using new nova
client with older nova server. Nova client needs to be always
releasable, and work with all nova server API versions out there.

Fixes bug #1173353

Change-Id: I2c07d109af4a35bc3b98dedaf991d5d3cc6fdd3b
Code cleanup in advance of flake8.

Change-Id: Ia2b463fdf3092aa72147eeda41faad4733fddd46
Migrate to flake8.

Fixes bug 1172444.

Change-Id: I0d8faa0819738456a28aaf5cc859f510a2b3ed68