Options.td: rename CCC{Driver,Debug}Opt to Internal{Driver,Debug}Opt

Also rename ccc_Group, ccc_driver_Group and ccc_Debug_Group similarly.

Differential Revision: http://llvm-reviews.chandlerc.com/D1218

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@187239 91177308-0d34-0410-b5e6-96231b3b80d8