Avoid AttributeError when no user is logged in and Issue.edit_allowed is called.
Avoid AttributeError when no user is logged in and Issue.edit_allowed is called.

arg0/rietveld,google-code-export/rietveld,berkus/rietveld,kscharding/integral-solutions-smxq,fuzan/rietveld,draem0507/rietveld,DeanHere/rietveld,nbodepallictr/touchites-codereview,Koulio/rietveld,nareshboddepalli/touchites-test,xtypebee/rietveld,nareshboddepalli/touchites-codereview,andyzsf/rietveld,rietveld-codereview/rietveld,v3ss0n/rietveld,fuzan/rietveld,fuzan/rietveld,nareshboddepalli/touchites-codereview,nbodepallictr/touchites-codereview,kscharding/integral-solutions-smxq,nareshboddepalli/touchites-test,berkus/rietveld,v3ss0n/rietveld,gavioto/rietveld,Koulio/rietveld,v3ss0n/rietveld,supriyantomaftuh/rietveld,rietveld-codereview/rietveld,DeanHere/rietveld,aungzanbaw/rietveld,ericmckean/rietveld,robfig/rietveld,ericmckean/rietveld,sajingeo/rietveld,rietveld-codereview/rietveld,gavioto/rietveld,salomon1184/rietveld,rietveld-codereview/rietveld,dushmis/rietveld,xtypebee/rietveld,sajingeo/rietveld,supriyantomaftuh/rietveld,andyzsf/rietveld,arg0/rietveld,foolonhill/rietveld,nbodepallictr/touchites-test,nareshboddepalli/touchites-test,foolonhill/rietveld,kscharding/integral-solutions-smxq,gco/rietveld,andyzsf/rietveld,aungzanbaw/rietveld,aungzanbaw/rietveld,sajingeo/rietveld,robfig/rietveld,google-code-export/rietveld,openlabs/cr.openlabs.co.in,xtypebee/rietveld,google-code-export/rietveld,salomon1184/rietveld,foolonhill/rietveld,Koulio/rietveld,arg0/rietveld,gco/rietveld,salomon1184/rietveld,nbodepallictr/touchites-codereview,draem0507/rietveld,draem0507/rietveld,dushmis/rietveld,DeanHere/rietveld,openlabs/cr.openlabs.co.in,supriyantomaftuh/rietveld,ericmckean/rietveld,robfig/rietveld,gavioto/rietveld,berkus/rietveld,nbodepallictr/touchites-test,gco/rietveld,openlabs/cr.openlabs.co.in,nbodepallictr/touchites-test,dushmis/rietveld,nareshboddepalli/touchites-codereview