Merge with crew-stable

mq: abort cleanly when invalid patch name is given to qguard

Close keepalive connections to fix server traceback

don't return uninitialized memory from bdiff.blocks() bdiff.blocks() returns a dummy match at the end of both files; the length of that chunk is never set, so it will sometimes contain random heap garbage. There are apparently workarounds for this elsewhere: # bdiff sometimes gives huge matches past eof, this check eats them,

web/server: disable address reuse option for BaseHTTPServer on windows On windows, a socket with the SO_REUSEADDR option set is able to bind to any port, even if there's already an active socket listening on it. test-http: check server address cannot be reused.

stdout raises EINVAL when flush() is called on a closed pipe under win32. Maybe the exception should be caught and translated at raise location instead (sshserver.py).

localrepo: stream_in may raise ZeroDivisionError with nul float elapsed argument.