Avoid re-using the same timeout for further watcher ops
Avoid re-using the same timeout for further watcher ops

Instead of re-using the same timeout that is passed into the
'run_watchers' function we should adjust that timeout after
each fetch so that the expected timeout the user gives to this
function is observed.

Change-Id: I5d171b1ac8b207213224f4e0f3909625de7275db

openstack/tooz,openstack/tooz