On uninstall, match the egg case via its extension
On uninstall, match the egg case via its extension

instead of egg_name since they don't seem to be unambiguous
also add a debug log in case no uninstall case match
(it would have made the debugging much easier)

closes #2293

nthall/pip,rbtcollins/pip,tdsmith/pip,qbdsoft/pip,qbdsoft/pip,jythontools/pip,ncoghlan/pip,xavfernandez/pip,ianw/pip,haridsv/pip,zenlambda/pip,erikrose/pip,pypa/pip,mindw/pip,caosmo/pip,natefoo/pip,James-Firth/pip,techtonik/pip,mujiansu/pip,graingert/pip,alex/pip,Gabriel439/pip,blarghmatey/pip,pradyunsg/pip,chaoallsome/pip,rouge8/pip,davidovich/pip,nthall/pip,wkeyword/pip,ChristopherHogan/pip,esc/pip,esc/pip,RonnyPfannschmidt/pip,jasonkying/pip,graingert/pip,rbtcollins/pip,erikrose/pip,chaoallsome/pip,sbidoul/pip,sbidoul/pip,sigmavirus24/pip,sigmavirus24/pip,benesch/pip,harrisonfeng/pip,habnabit/pip,luzfcb/pip,squidsoup/pip,fiber-space/pip,nthall/pip,atdaemon/pip,benesch/pip,supriyantomaftuh/pip,atdaemon/pip,blarghmatey/pip,squidsoup/pip,luzfcb/pip,habnabit/pip,esc/pip,mujiansu/pip,haridsv/pip,jasonkying/pip,habnabit/pip,mujiansu/pip,zorosteven/pip,KarelJakubec/pip,ianw/pip,ChristopherHogan/pip,blarghmatey/pip,pjdelport/pip,wkeyword/pip,zvezdan/pip,willingc/pip,xavfernandez/pip,fiber-space/pip,zorosteven/pip,graingert/pip,jamezpolley/pip,h4ck3rm1k3/pip,techtonik/pip,dstufft/pip,jythontools/pip,squidsoup/pip,pfmoore/pip,Gabriel439/pip,RonnyPfannschmidt/pip,rouge8/pip,chaoallsome/pip,yati-sagade/pip,tdsmith/pip,tdsmith/pip,ncoghlan/pip,willingc/pip,harrisonfeng/pip,pfmoore/pip,rbtcollins/pip,natefoo/pip,xavfernandez/pip,supriyantomaftuh/pip,mindw/pip,benesch/pip,jmagnusson/pip,prasaianooz/pip,caosmo/pip,yati-sagade/pip,pradyunsg/pip,jamezpolley/pip,prasaianooz/pip,Gabriel439/pip,ncoghlan/pip,zenlambda/pip,harrisonfeng/pip,alex/pip,luzfcb/pip,jamezpolley/pip,zvezdan/pip,pjdelport/pip,jmagnusson/pip,techtonik/pip,natefoo/pip,pypa/pip,ChristopherHogan/pip,qbdsoft/pip,jythontools/pip,yati-sagade/pip,rouge8/pip,James-Firth/pip,erikrose/pip,davidovich/pip,mindw/pip,zorosteven/pip,prasaianooz/pip,caosmo/pip,jmagnusson/pip,dstufft/pip,KarelJakubec/pip,dstufft/pip,supriyantomaftuh/pip,pjdelport/pip,alex/pip,atdaemon/pip,davidovich/pip,h4ck3rm1k3/pip,sigmavirus24/pip,fiber-space/pip,willingc/pip,h4ck3rm1k3/pip,wkeyword/pip,haridsv/pip,zenlambda/pip,jasonkying/pip,RonnyPfannschmidt/pip,zvezdan/pip,KarelJakubec/pip,James-Firth/pip