Remove XML support

XML support in Neutron has always been a second class feature to the
JSON API and broken for many extensions and outputs. The XML API been marked as
deprecated for the Icehouse and Juno release and is ready for removal in
Kilo.

Change-Id: I611aa9382ba3bfb08b2970c63e83b0fdd3d2e8a4
Closes-Bug: #1380787
Fix 'Length too long' error in neutron-dsvm-functional tests

testr is occasionally failing with 'Length too long' for
neutron-dsvm-functional test cases.

The issue is seen when the size of the testr log file size goes into MBs.

(Please see the bug comments for the details on the testr logs)

This patch fixes the issue by disabling debug logs in the tests.

Change-Id: I48fc9d14f6886f86761038ee4d106fbbe59b6890
Closes-bug: #1382579
Merge "Fix 'Length too long' error in neutron-dsvm-functional tests"
Merge "Remove XML support"