Remove `product` reimplementation - unused
Remove `product` reimplementation - unused

No longer needed from 2.6 up (in itertools)

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