Delete FIP namespace when last VM is deleted

On a compute node when the last VM with a floating IP association
is deleted, the L3 agent did not delete the fip namespace. However
the api server has already deleted the fip agent external gateway
port from the database.

This problem is happening on DVRs because the deletion of a VM port,
in addition to a floating IP disassociation, may also result in the
removal of the external gateway port binding AND the removal of the
fip agent external gateway port.

When the L3 agent is handling a routers_updated notification, it is
not processing floating ip address updates when the router has both
a floating ip disassociated and a external gateway port deleted.
This patch corrects this problem.

Closes-bug: #1377156
Change-Id: I86bdef7c9d988cb9d87c88adde55548d459f29a5
iptables_manager: Fix get_binary_name for eventlet

The inspect trick used by get_binary_name does not work for
eventlet non-main threads.  It's actually the case for ofagent
and in that case it yields something like "greenthread.py",
which is not desirable because this module assumes it different
for each programs.  This commit fixes the problem by switching
to use sys.argv.

Closes-Bug: #1367075
Change-Id: I8e765882c58d9991a37f0bbb52cdccc406e287bd
Update i18n translation for BigSwitch plugin log msg's

All the log messages now have the required hints. In addition to this
debug messages are not translated.

This is done for the plugins/bigswitch and plugins/common directories

Change-Id: If661fcfac3b22c8cffee65c3e8073e746ef3468e
Merge "Update i18n translation for BigSwitch plugin log msg's"
Merge "iptables_manager: Fix get_binary_name for eventlet"
Merge "Delete FIP namespace when last VM is deleted"