Better error reporting when curl is not installed
Better error reporting when curl is not installed

If buck build was done on a system without curl installed
a misleading error message would be printed out:

  error creating directory /home/user/.gerritcodereview/buck-cache

However, the real error was that invocation of curl failed. Since
it was an OSError it was handled with the wrong except block.

Separate handling of the OSError for the folder creation and curl
invocation.

Change-Id: Ic7e7c2c2704ea4cbccff4689dffe17a436108395

supriyantomaftuh/gerrit,netroby/gerrit,TonyChai24/test,GerritCodeReview/gerrit,gerrit-review/gerrit,supriyantomaftuh/gerrit,pkdevbox/gerrit,midnightradio/gerrit,midnightradio/gerrit,GerritCodeReview/gerrit,jackminicloud/test,gracefullife/gerrit,Saulis/gerrit,WANdisco/gerrit,Overruler/gerrit,qtproject/qtqa-gerrit,thesamet/gerrit,anminhsu/gerrit,thesamet/gerrit,bootstraponline-archive/gerrit-mirror,gcoders/gerrit,pkdevbox/gerrit,bpollack/gerrit,gracefullife/gerrit,thinkernel/gerrit,gcoders/gerrit,bpollack/gerrit,jackminicloud/test,bpollack/gerrit,thinkernel/gerrit,netroby/gerrit,netroby/gerrit,pkdevbox/gerrit,midnightradio/gerrit,bootstraponline-archive/gerrit-mirror,anminhsu/gerrit,renchaorevee/gerrit,renchaorevee/gerrit,WANdisco/gerrit,anminhsu/gerrit,thesamet/gerrit,bpollack/gerrit,thesamet/gerrit,Distrotech/gerrit,thinkernel/gerrit,WANdisco/gerrit,thinkernel/gerrit,joshuawilson/merrit,Saulis/gerrit,Saulis/gerrit,TonyChai24/test,quyixia/gerrit,dwhipstock/gerrit,Distrotech/gerrit,MerritCR/merrit,GerritCodeReview/gerrit,Overruler/gerrit,Seinlin/gerrit,supriyantomaftuh/gerrit,midnightradio/gerrit,gracefullife/gerrit,jackminicloud/test,hdost/gerrit,thinkernel/gerrit,renchaorevee/gerrit,joshuawilson/merrit,TonyChai24/test,gracefullife/gerrit,GerritCodeReview/gerrit,bootstraponline-archive/gerrit-mirror,thinkernel/gerrit,Distrotech/gerrit,bpollack/gerrit,bootstraponline-archive/gerrit-mirror,Overruler/gerrit,bootstraponline-archive/gerrit-mirror,Distrotech/gerrit,quyixia/gerrit,Seinlin/gerrit,Team-OctOS/host_gerrit,gcoders/gerrit,jackminicloud/test,anminhsu/gerrit,renchaorevee/gerrit,pkdevbox/gerrit,Saulis/gerrit,Seinlin/gerrit,renchaorevee/gerrit,dwhipstock/gerrit,bpollack/gerrit,Overruler/gerrit,gerrit-review/gerrit,hdost/gerrit,gerrit-review/gerrit,Team-OctOS/host_gerrit,gracefullife/gerrit,MerritCR/merrit,quyixia/gerrit,midnightradio/gerrit,anminhsu/gerrit,pkdevbox/gerrit,Overruler/gerrit,bootstraponline-archive/gerrit-mirror,dwhipstock/gerrit,qtproject/qtqa-gerrit,netroby/gerrit,gerrit-review/gerrit,TonyChai24/test,hdost/gerrit,Overruler/gerrit,gcoders/gerrit,quyixia/gerrit,Seinlin/gerrit,quyixia/gerrit,quyixia/gerrit,Saulis/gerrit,Seinlin/gerrit,MerritCR/merrit,GerritCodeReview/gerrit,renchaorevee/gerrit,Team-OctOS/host_gerrit,dwhipstock/gerrit,WANdisco/gerrit,gerrit-review/gerrit,Distrotech/gerrit,dwhipstock/gerrit,supriyantomaftuh/gerrit,GerritCodeReview/gerrit,hdost/gerrit,gcoders/gerrit,dwhipstock/gerrit,MerritCR/merrit,renchaorevee/gerrit,qtproject/qtqa-gerrit,gcoders/gerrit,hdost/gerrit,jackminicloud/test,jackminicloud/test,dwhipstock/gerrit,joshuawilson/merrit,anminhsu/gerrit,Team-OctOS/host_gerrit,supriyantomaftuh/gerrit,supriyantomaftuh/gerrit,WANdisco/gerrit,hdost/gerrit,jackminicloud/test,Distrotech/gerrit,qtproject/qtqa-gerrit,GerritCodeReview/gerrit,joshuawilson/merrit,Team-OctOS/host_gerrit,thesamet/gerrit,TonyChai24/test,midnightradio/gerrit,WANdisco/gerrit,joshuawilson/merrit,netroby/gerrit,MerritCR/merrit,pkdevbox/gerrit,TonyChai24/test,anminhsu/gerrit,Seinlin/gerrit,gerrit-review/gerrit,thinkernel/gerrit,MerritCR/merrit,Team-OctOS/host_gerrit,Distrotech/gerrit,Saulis/gerrit,netroby/gerrit,gerrit-review/gerrit,joshuawilson/merrit,qtproject/qtqa-gerrit,MerritCR/merrit,joshuawilson/merrit,thesamet/gerrit,qtproject/qtqa-gerrit,netroby/gerrit,joshuawilson/merrit,quyixia/gerrit,GerritCodeReview/gerrit,Team-OctOS/host_gerrit,WANdisco/gerrit,qtproject/qtqa-gerrit,hdost/gerrit,TonyChai24/test,supriyantomaftuh/gerrit,thesamet/gerrit,pkdevbox/gerrit,gcoders/gerrit,Seinlin/gerrit,MerritCR/merrit