Fixed issue: rax:roles in method references were not handled correctly.

Copied method after normalization was keeping a reference to its
source. This is well and good, but the rax:roles transform changes the
copy, so assumtions that copy and source are identitcal were being
broken.

The fix, simply removes the reference to the source if rax:roles are
applicable.
Merge pull request #191 from RackerWilliams/rax-role-fix

Fixed issue: rax:roles in method references were not handled correctly.