fs: dlm: interrupt posix locks only when process is killed

If a posix lock request is waiting for a result from user space
(dlm_controld), do not let it be interrupted unless the process
is killed. This reverts commit a6b1533e ("dlm: make posix locks
interruptible"). The problem with the interruptible change is
that all locks were cleared on any signal interrupt. If a signal
was received that did not terminate the process, the process
could continue running after all its dlm posix locks had been
cleared. A future patch will add cancelation to allow proper
interruption.

Cc: stable@vger.kernel.org
Fixes: a6b1533e ("dlm: make posix locks interruptible")
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>