Restore RSpec2 support

It seems simple to restore support for RSpec 2 without messing up the
matcher code too much.

Change-Id: I283cb3c84e9b03bf84d7c9414a054d9e3f95f66b
Reviewed-on: http://gerrit.causes.com/45260
Reviewed-by: Joe Lencioni <joe.lencioni@brigade.com>
Tested-by: Joe Lencioni <joe.lencioni@brigade.com>
Update changelog

We've had a couple of commits recently but did not update the changelog.

Change-Id: I317e950c2fccf7857e2dbbcc8f5f44ae61ab015c
Reviewed-on: http://gerrit.causes.com/45261
Reviewed-by: Joe Lencioni <joe.lencioni@brigade.com>
Tested-by: Joe Lencioni <joe.lencioni@brigade.com>