Handle duplicate email addresses in Message entities
Handle duplicate email addresses in Message entities

Android's GAE store has duplicate emails listed on the same
change message.  This really shouldn't have happened, and
its pointless to have duplicates in the same message list,
so run them all through a set to remove the duplicates.

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

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