Clean up the webkitpy.layout_tests.servers.apache_http code

... in preparation for implementing the win32 port as well. Part of this
clean up removes some escaping that may have been necessary in cygwin python,
but I don't really have any interest in supporting running the layout
tests in that mode (I'm not even sure if it works given the extensive use
of multiprocessing now).

R=scottmg@chromium.org
BUG=30536

Review URL: https://codereview.chromium.org/159983005

git-svn-id: svn://svn.chromium.org/blink/trunk@167129 bbb929c8-8fbe-4397-9dbb-9b2b20218538