Remove obsolete Makefile.am

We don't use GNU automake anymore

Change-Id: I52d6a2f7d0e3d6105d9d77ef1a26b17d1f6c539d
Reviewed-on: http://review.couchbase.org/35450
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>