CP-4465 contribution: reduce logging of low-value messages
 * log less in block_device_io.action_writedelta
 * shorten a common log line in xapi_session.ml

Signed-off-by: Thomas Sanders <thomas.sanders@citrix.com>
Altering get_bridge_name_vswitch() to work correctly with VLANs.
VLAN-tagged networks/ports are connected to a "fake bridge" device.
Most ovs-* commands will not work with a fake bridge
device, so this function needs to return the true parent bridge
device name, not the fake bridge.  Otherwise, subsequent calls
in this script to configure port locking via ovs-ofctl will
(silently) fail, and port locking will not activate.

Signed-off-by: Kevin Tower <ktower@towerfamily.org>
Merge pull request #1180 from ktower/master

Fix scripts/setup-vif-rules to work with VLAN-tagged networks
Merge pull request #1197 from thomassa/lesslog

CP-4465 contribution: reduce logging of low-value messages