Rename MacMini slaves and add secondary slaves
Rename MacMini slaves and add secondary slaves

Secondary slaves won't enable until new machines are brought up.
Review URL: https://codereview.appspot.com/6464061

git-svn-id: 32fc27f4dcfb6c0385cd9719852b95fe6680452d@5089 2bbb7eff-a529-9590-31e7-b0007b416f81

Tiger66639/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot,Tiger66639/skia-buildbot