serialize remoteCommand

Remotecommands updates are started in order, but are not garanteed to finish in order
We introduce a lock to make sure everything is serialized.

With buildbot nine, lots of the updates are doing asyncrhnous stuff like log update
and thus are definitly not finishing in order, thus a whole new class of weird behaviour.

Signed-off-by: Pierre Tardy <pierre.tardy@intel.com>
integration test for TRAC-3024
factorize integration test's forceBuild

Signed-off-by: Pierre Tardy <pierre.tardy@intel.com>
Remove remaining c['www']['url']

This removes all the occurrences of ['www']['url'] after commit b53998a3fac5f15d0a1d5c7bd90561f7dfec779d