Bump Touch.Unit to get fix for running watchOS tests on device when the mac has multiple IP addresses. (#2858)

commit spouliot/Touch.Unit@b5b227e80b
Author: Rolf Bjarne Kvinge <rolf@xamarin.com>
Date:   Wed Oct 4 11:45:32 2017 +0200

    [TouchRunner] Improve logging output.

    When asked to write logs to a TCP host:port, and given multiple hostnames, we
    try to connect to all of them to see which hostname works.

    This logic does not necessarily work when asked to write to a http host:port
    (it would have to be implemented), which means that when given multiple
    hostnames, we'd enter a special case, not connecting to anything, and soon
    throwing a NullReferenceException.

    So refactor the logic slightly: we now only try to select the hostname when
    asked to write to a TCP host:port; when asked to write to a HTTP host:port we
    just select the first hostname (which is still better than throwing a NRE).

    We also don't unnecessarily try to resolve hostnames when asked to write logs
    to a file, and make absolutely sure there's no way to not have a log to write
    to by writing to Console.Out if we can't do anything else.

external/Touch.Unit

@@ -1 +1 @@
-Subproject commit 8f1e19d731c7490993e5b25aaa2fc340498079b5
+Subproject commit b5b227e80b7ceeb04ab3e6b85b0853784438f129