macos: fix growlagent icon handling

macos: fix growlagent icon handling

the whole of the api used for icon handling when you steal it
from a resource fork is deprecated in new macos. fine. we'll just make
an app bundle by cheating, move andy into a standalone icns file,
install him into the "bundle" and open it the macos way.

Reviewed-on: http://gerrit.openafs.org/7786
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>
Tested-by: Derrick Brashear <shadow@dementix.org>
(cherry picked from commit 3dd230e8595e2b9635d6ec412a145ae3be229b7a)

Change-Id: I9a439601058a4c2f32cbe687865a9143d56b92bf
Reviewed-on: http://gerrit.openafs.org/8781
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Paul Smeddle <paul.smeddle@gmail.com>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>