Don't backup DeltaContent as its huge and unused by Gerrit2
Don't backup DeltaContent as its huge and unused by Gerrit2

The DeltaContent entity type is the bulk of the data in the data
store for any Gerrit application.  We don't use it when we convert
a version 1 database to version 2, and the data is easily recreated
from any Git repository which has the necessary objects, which is
typically found on the mgrapp server.

Skipping it during backup improves backup speed and reduces the
chances the backup fails.  It also makes the backup smaller once
we get it into PostgreSQL, making it easier to dump the database
and ship the dump file around.

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

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