ipvs: Use schedule_timeout_interruptible() instead of msleep_interruptible()

So that kthread_stop() can wake up the thread and we don't have to wait one
second in the worst case for the daemon to actually stop.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Simon Horman <horms@verge.net.au>