BUG: Fix unbound local in exception handling in core/index
BUG: Fix unbound local in exception handling in core/index

Only would occur if both enumerations failed. better way to handle than
try/except.

cbertinato/pandas,dsm054/pandas,GuessWhoSamFoo/pandas,louispotok/pandas,jorisvandenbossche/pandas,cbertinato/pandas,cbertinato/pandas,dsm054/pandas,zfrenchee/pandas,rs2/pandas,jreback/pandas,kdebrab/pandas,winklerand/pandas,kdebrab/pandas,GuessWhoSamFoo/pandas,nmartensen/pandas,jreback/pandas,louispotok/pandas,cython-testbed/pandas,cython-testbed/pandas,zfrenchee/pandas,jreback/pandas,Winand/pandas,amolkahat/pandas,dsm054/pandas,winklerand/pandas,MJuddBooth/pandas,cython-testbed/pandas,amolkahat/pandas,pratapvardhan/pandas,TomAugspurger/pandas,jorisvandenbossche/pandas,DGrady/pandas,dsm054/pandas,jreback/pandas,datapythonista/pandas,winklerand/pandas,Winand/pandas,nmartensen/pandas,toobaz/pandas,toobaz/pandas,linebp/pandas,gfyoung/pandas,linebp/pandas,zfrenchee/pandas,louispotok/pandas,pandas-dev/pandas,GuessWhoSamFoo/pandas,jmmease/pandas,DGrady/pandas,jmmease/pandas,Winand/pandas,MJuddBooth/pandas,jmmease/pandas,winklerand/pandas,linebp/pandas,linebp/pandas,Winand/pandas,jmmease/pandas,DGrady/pandas,DGrady/pandas,datapythonista/pandas,GuessWhoSamFoo/pandas,harisbal/pandas,pratapvardhan/pandas,louispotok/pandas,cython-testbed/pandas,amolkahat/pandas,jreback/pandas,GuessWhoSamFoo/pandas,cbertinato/pandas,nmartensen/pandas,linebp/pandas,Winand/pandas,pratapvardhan/pandas,pandas-dev/pandas,winklerand/pandas,gfyoung/pandas,Winand/pandas,toobaz/pandas,DGrady/pandas,cbertinato/pandas,rs2/pandas,datapythonista/pandas,harisbal/pandas,toobaz/pandas,datapythonista/pandas,amolkahat/pandas,kdebrab/pandas,rs2/pandas,jorisvandenbossche/pandas,winklerand/pandas,MJuddBooth/pandas,pratapvardhan/pandas,pratapvardhan/pandas,dsm054/pandas,cython-testbed/pandas,jmmease/pandas,pandas-dev/pandas,DGrady/pandas,rs2/pandas,nmartensen/pandas,jorisvandenbossche/pandas,MJuddBooth/pandas,pandas-dev/pandas,gfyoung/pandas,jmmease/pandas,harisbal/pandas,harisbal/pandas,TomAugspurger/pandas,nmartensen/pandas,kdebrab/pandas,MJuddBooth/pandas,TomAugspurger/pandas,louispotok/pandas,amolkahat/pandas,harisbal/pandas,linebp/pandas,nmartensen/pandas,gfyoung/pandas,kdebrab/pandas,TomAugspurger/pandas,toobaz/pandas,gfyoung/pandas,zfrenchee/pandas,zfrenchee/pandas