kill_wait: fix timeout error reporting
kill_wait: fix timeout error reporting

Used to look like this:

	killing process 27366 "bash" with signal 15: badness 539, VmRSS 7464 MiB
	timeout waiting for pid 27366 after signal 15
	kill failed: Success. Sleeping 1 second

https://github.com/rfjakob/earlyoom/issues/121

rfjakob/earlyoom,rfjakob/earlyoom,rfjakob/earlyoom,rfjakob/earlyoom