Fix potential issue stopping process services.

Fix potential issue stopping process services.

Process services undergoing smooth recovery count as "STARTED" but have
a pid of -1, or a valid pid but with a process launch underway (waiting
for exec status). If all dependencies stopped at the wrong time, the
behaviour was to treat the service as stopped, but the smooth recovery
was still kicking on and could cause an issue if it "succeeded" after
the service was supposedly terminated.

To resolve this, don't send a kill signal to a process during smooth
recovery (i.e. if waiting_for_execstat is true) and send it once
recovery has completed instead.