client: use subprocess.communicate() to shut down server process This allows us to get stderr output with no deadlock risk. Also, it should fix possible deadlock issue at server.wait(). https://docs.python.org/2.7/library/subprocess.html#subprocess.Popen.wait

from hglib.util import b

changeset = b('{rev}\\0{node}\\0{tags}\\0{branch}\\0{author}'
              '\\0{desc}\\0{date}\\0')