Fix PIDLockFile.acquire() may loop indefinitely
Fix PIDLockFile.acquire() may loop indefinitely

end_time takes timeout into account, so when time.time()
does hit the end_time, we should check if timeout was
set or not and throw either LockTimeout or AlreadyLocked.

Closes-Bug: #1472101
Change-Id: I1f369628e765a173ff0cafd01c31eca725b41cae

allieus/pylockfile