Minor tweak to handle not passing options to parse_requirements.
Minor tweak to handle not passing options to parse_requirements.

Options is supposed to be an optional argument, this makes it optional.
harrisonfeng/pip,caosmo/pip,haridsv/pip,rouge8/pip,esc/pip,jamezpolley/pip,chaoallsome/pip,RonnyPfannschmidt/pip,zvezdan/pip,qwcode/pip,blarghmatey/pip,ChristopherHogan/pip,KarelJakubec/pip,erikrose/pip,zvezdan/pip,habnabit/pip,Ivoz/pip,benesch/pip,dstufft/pip,erikrose/pip,natefoo/pip,atdaemon/pip,h4ck3rm1k3/pip,jasonkying/pip,squidsoup/pip,jamezpolley/pip,squidsoup/pip,nthall/pip,benesch/pip,patricklaw/pip,ncoghlan/pip,luzfcb/pip,zorosteven/pip,tdsmith/pip,esc/pip,prasaianooz/pip,pfmoore/pip,jamezpolley/pip,chaoallsome/pip,luzfcb/pip,minrk/pip,zenlambda/pip,nthall/pip,mujiansu/pip,ChristopherHogan/pip,sbidoul/pip,pradyunsg/pip,benesch/pip,jythontools/pip,rbtcollins/pip,zenlambda/pip,KarelJakubec/pip,willingc/pip,Carreau/pip,pfmoore/pip,yati-sagade/pip,sigmavirus24/pip,RonnyPfannschmidt/pip,tdsmith/pip,Carreau/pip,qwcode/pip,xavfernandez/pip,mattrobenolt/pip,willingc/pip,harrisonfeng/pip,Gabriel439/pip,msabramo/pip,graingert/pip,dstufft/pip,sigmavirus24/pip,davidovich/pip,zenlambda/pip,supriyantomaftuh/pip,James-Firth/pip,dstufft/pip,sigmavirus24/pip,atdaemon/pip,erikrose/pip,minrk/pip,jmagnusson/pip,graingert/pip,ncoghlan/pip,KarelJakubec/pip,xavfernandez/pip,ncoghlan/pip,haridsv/pip,ianw/pip,nthall/pip,graingert/pip,h4ck3rm1k3/pip,pjdelport/pip,davidovich/pip,chaoallsome/pip,fiber-space/pip,jythontools/pip,jasonkying/pip,pjdelport/pip,pradyunsg/pip,alex/pip,caosmo/pip,rouge8/pip,pjdelport/pip,jasonkying/pip,zorosteven/pip,yati-sagade/pip,techtonik/pip,blarghmatey/pip,natefoo/pip,Gabriel439/pip,supriyantomaftuh/pip,techtonik/pip,willingc/pip,alquerci/pip,yati-sagade/pip,techtonik/pip,zorosteven/pip,Ivoz/pip,blarghmatey/pip,alex/pip,xavfernandez/pip,mujiansu/pip,jmagnusson/pip,msabramo/pip,wkeyword/pip,ianw/pip,pypa/pip,jythontools/pip,qbdsoft/pip,rbtcollins/pip,jmagnusson/pip,patricklaw/pip,fiber-space/pip,alex/pip,luzfcb/pip,atdaemon/pip,cjerdonek/pip,alquerci/pip,davidovich/pip,cjerdonek/pip,James-Firth/pip,rouge8/pip,radiosilence/pip,wkeyword/pip,tdsmith/pip,fiber-space/pip,habnabit/pip,Gabriel439/pip,habnabit/pip,supriyantomaftuh/pip,zvezdan/pip,natefoo/pip,qbdsoft/pip,mujiansu/pip,haridsv/pip,prasaianooz/pip,ChristopherHogan/pip,rbtcollins/pip,mattrobenolt/pip,h4ck3rm1k3/pip,squidsoup/pip,mindw/pip,caosmo/pip,esc/pip,harrisonfeng/pip,pypa/pip,prasaianooz/pip,sbidoul/pip,James-Firth/pip,mindw/pip,wkeyword/pip,qbdsoft/pip,mindw/pip,RonnyPfannschmidt/pip