status: add more complete tests for --rev The 'status --rev' code is not very well tested, which has bitten us as recently as in issue4321. Let's add some more tests, some of which uncover bugs. Remove the few existing tests that are now covered in a more thorough and consistent way.

cmdserver: include pid of server handling requests in hello message Because unix-mode server forks child process per connection, client does not know the pid of the server that will handle requests. The pid is necessary to interrupt hung process: 1. client connects to socket server 2. server accepts the connection, forks, and tells pid 3. client requests "runcommand pull" .. hung .. 4. client sends SIGINT to the (forked) server 5. server returns from I/O wait Note that getsockopt(SO_PEERCRED) of Linux cannot be used because the server fork()s after accept().

run-tests: clean up unused globals that were removed by tests-refactor series They were demoted to instance variables by cb88d4a04f58, 1ad7aabba14e, 93511a595766, 2e1aa8c1ee37, 8e7b0f4d6ac7 and 02087bc4f143.