Set the destination of the welcome wizard to '/' if missing
Set the destination of the welcome wizard to '/' if missing

If the user arrived at the welcome page with no specific destination
URL we should encode '/' in the subsequent requests so they have
a place to go when the wizard is completed.

Signed-off-by: Shawn O. Pearce <f3ea74d906fa9fe97c1fef6bad9cb871485c7045@google.com>

thinkernel/gerrit,GerritCodeReview/gerrit-attic,WANdisco/gerrit,Distrotech/gerrit,hdost/gerrit,skurfuerst/gerrit,evanchueng/gerrit,teamblueridge/gerrit,gracefullife/gerrit,midnightradio/gerrit,rtyley/mini-git-server,Seinlin/gerrit,basilgor/gerrit,gcoders/gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit-attic,atdt/gerrit,gerrit-review/gerrit,WANdisco/gerrit,dwhipstock/gerrit,anminhsu/gerrit,dwhipstock/gerrit,gerrit-review/gerrit,Team-OctOS/host_gerrit,quyixia/gerrit,GerritCodeReview/gerrit,Shrews/PyGerrit,sudosurootdev/gerrit,Team-OctOS/host_gerrit,skurfuerst/gerrit,netroby/gerrit,Distrotech/gerrit,CandyShop/gerrit,m1kah/gerrit-contributions,anminhsu/gerrit,WANdisco/gerrit,hdost/gerrit,joshuawilson/merrit,quyixia/gerrit,bpollack/gerrit,supriyantomaftuh/gerrit,ashang/aaron-gerrit,gcoders/gerrit,duboisf/gerrit,quyixia/gerrit,joshuawilson/merrit,zommarin/gerrit,pkdevbox/gerrit,gracefullife/gerrit,makholm/gerrit-ceremony,joshuawilson/merrit,TonyChai24/test,bootstraponline-archive/gerrit-mirror,supriyantomaftuh/gerrit,midnightradio/gerrit,ckamm/gerrit,ashang/aaron-gerrit,TonyChai24/test,cjh1/gerrit,Distrotech/gerrit,Distrotech/gerrit,Team-OctOS/host_gerrit,ashang/aaron-gerrit,Saulis/gerrit,duboisf/gerrit,teamblueridge/gerrit,pkdevbox/gerrit,Shrews/PyGerrit,quyixia/gerrit,thesamet/gerrit,Seinlin/gerrit,catrope/gerrit,midnightradio/gerrit,bootstraponline-archive/gerrit-mirror,jeblair/gerrit,sudosurootdev/gerrit,catrope/gerrit,zommarin/gerrit,WANdisco/gerrit,pkdevbox/gerrit,renchaorevee/gerrit,skurfuerst/gerrit,bootstraponline-archive/gerrit-mirror,WANdisco/gerrit,MerritCR/merrit,CandyShop/gerrit,GerritCodeReview/gerrit,Distrotech/gerrit,pkdevbox/gerrit,atdt/gerrit,evanchueng/gerrit,hdost/gerrit,Distrotech/gerrit,jackminicloud/test,zommarin/gerrit,makholm/gerrit-ceremony,Overruler/gerrit,dwhipstock/gerrit,WANdisco/gerrit,thesamet/gerrit,thesamet/gerrit,qtproject/qtqa-gerrit,dwhipstock/gerrit,bpollack/gerrit,jackminicloud/test,sudosurootdev/gerrit,m1kah/gerrit-contributions,gracefullife/gerrit,qtproject/qtqa-gerrit,ckamm/gerrit,gcoders/gerrit,joshuawilson/merrit,1yvT0s/gerrit,thinkernel/gerrit,anminhsu/gerrit,thinkernel/gerrit,renchaorevee/gerrit,supriyantomaftuh/gerrit,Saulis/gerrit,keerath/gerrit_newssh,keerath/gerrit_newssh,quyixia/gerrit,basilgor/gerrit,austinchic/Gerrit,hdost/gerrit,austinchic/Gerrit,sudosurootdev/gerrit,supriyantomaftuh/gerrit,Seinlin/gerrit,Overruler/gerrit,gerrit-review/gerrit,GerritCodeReview/gerrit-attic,Team-OctOS/host_gerrit,bpollack/gerrit,pkdevbox/gerrit,atdt/gerrit,gerrit-review/gerrit,makholm/gerrit-ceremony,makholm/gerrit-ceremony,evanchueng/gerrit,Seinlin/gerrit,qtproject/qtqa-gerrit,MerritCR/merrit,MerritCR/merrit,gcoders/gerrit,netroby/gerrit,basilgor/gerrit,midnightradio/gerrit,Seinlin/gerrit,midnightradio/gerrit,Overruler/gerrit,bpollack/gerrit,CandyShop/gerrit,ashang/aaron-gerrit,austinchic/Gerrit,duboisf/gerrit,austinchic/Gerrit,ckamm/gerrit,MerritCR/merrit,pkdevbox/gerrit,catrope/gerrit,evanchueng/gerrit,netroby/gerrit,skurfuerst/gerrit,MerritCR/merrit,gerrit-review/gerrit,netroby/gerrit,TonyChai24/test,Overruler/gerrit,gerrit-review/gerrit,gcoders/gerrit,cjh1/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,Seinlin/gerrit,qtproject/qtqa-gerrit,hdost/gerrit,hdost/gerrit,CandyShop/gerrit,anminhsu/gerrit,Team-OctOS/host_gerrit,ckamm/gerrit,gracefullife/gerrit,gcoders/gerrit,netroby/gerrit,teamblueridge/gerrit,pkdevbox/gerrit,Saulis/gerrit,1yvT0s/gerrit,m1kah/gerrit-contributions,joshuawilson/merrit,teamblueridge/gerrit,renchaorevee/gerrit,Distrotech/gerrit,jackminicloud/test,anminhsu/gerrit,1yvT0s/gerrit,TonyChai24/test,ashang/aaron-gerrit,Saulis/gerrit,zommarin/gerrit,renchaorevee/gerrit,supriyantomaftuh/gerrit,rtyley/mini-git-server,thesamet/gerrit,Shrews/PyGerrit,jackminicloud/test,supriyantomaftuh/gerrit,cjh1/gerrit,Team-OctOS/host_gerrit,TonyChai24/test,dwhipstock/gerrit,zommarin/gerrit,atdt/gerrit,basilgor/gerrit,joshuawilson/merrit,GerritCodeReview/gerrit,supriyantomaftuh/gerrit,MerritCR/merrit,joshuawilson/merrit,midnightradio/gerrit,quyixia/gerrit,WANdisco/gerrit,duboisf/gerrit,jackminicloud/test,GerritCodeReview/gerrit,MerritCR/merrit,sudosurootdev/gerrit,Saulis/gerrit,m1kah/gerrit-contributions,keerath/gerrit_newssh,GerritCodeReview/gerrit,atdt/gerrit,TonyChai24/test,thinkernel/gerrit,joshuawilson/merrit,thinkernel/gerrit,renchaorevee/gerrit,cjh1/gerrit,Overruler/gerrit,quyixia/gerrit,keerath/gerrit_newssh,TonyChai24/test,catrope/gerrit,jackminicloud/test,thesamet/gerrit,anminhsu/gerrit,gcoders/gerrit,Seinlin/gerrit,thesamet/gerrit,keerath/gerrit_newssh,jeblair/gerrit,renchaorevee/gerrit,thinkernel/gerrit,renchaorevee/gerrit,dwhipstock/gerrit,netroby/gerrit,netroby/gerrit,hdost/gerrit,Shrews/PyGerrit,bootstraponline-archive/gerrit-mirror,bpollack/gerrit,Saulis/gerrit,jackminicloud/test,bootstraponline-archive/gerrit-mirror,CandyShop/gerrit,qtproject/qtqa-gerrit,basilgor/gerrit,bootstraponline-archive/gerrit-mirror,jeblair/gerrit,dwhipstock/gerrit,GerritCodeReview/gerrit,anminhsu/gerrit,ckamm/gerrit,bpollack/gerrit,1yvT0s/gerrit,Team-OctOS/host_gerrit,thesamet/gerrit,gerrit-review/gerrit,Overruler/gerrit,MerritCR/merrit,1yvT0s/gerrit,thinkernel/gerrit,jeblair/gerrit,evanchueng/gerrit,gracefullife/gerrit,qtproject/qtqa-gerrit,teamblueridge/gerrit