Remove argument "watch_log = "
Remove argument "watch_log = "

This argument was marked deprecated in commit
I53fe014e80b507acf77a3c109179685e2e50200c,
Also there is no usage of argument watch_log in
other projects. It's safe to remove it now.

Change-Id: I49a6d9cf38957e661422f6175e86a5c3377d3b2d

eayunstack/neutron,openstack/neutron,huntxu/neutron,eayunstack/neutron,mahak/neutron,mahak/neutron,noironetworks/neutron,openstack/neutron,mahak/neutron,noironetworks/neutron,openstack/neutron,huntxu/neutron