[NEXUS-6004] replace CompositeException usage with helper to attach suppressed exceptions
Squashed commit of the following:

commit 6765abea4e124ba6d27553e2cb1e13e2e2642cd2
Merge: 567e1d3 3675dd6
Author: Jason Dillon <jason@planet57.com>
Date:   Sat Nov 9 14:10:01 2013 -0800

    Merge branch 'nexus-2.7.x' into NEXUS-6004-composite-supressed-exceptions

commit 567e1d3c4d6c9558cae08564ae419a35af13d264
Author: Jason Dillon <jason@planet57.com>
Date:   Sat Nov 9 13:44:23 2013 -0800

    Update to goodies 1.7.4-SNAPSHOT
    Use Throwables2.composite() helper

commit 4de98801fa43ff18e660b19ca68aad22e6015552
Author: Jason Dillon <jason@planet57.com>
Date:   Fri Nov 8 15:03:01 2013 -0800

    [NEXUS-6004] replace CompositeException usage with helper to attach suppressed exceptions