Fix endless loop when no addressbooks.
Fix endless loop when no addressbooks.

michaelletzgus/nextcloud-server,lrytz/core,pmattern/server,whitekiba/server,owncloud/core,IljaN/core,phil-davis/core,nextcloud/server,lrytz/core,bluelml/core,endsguy/server,pixelipo/server,Ardinis/server,cernbox/core,pixelipo/server,michaelletzgus/nextcloud-server,IljaN/core,nextcloud/server,Ardinis/server,sharidas/core,nextcloud/server,andreas-p/nextcloud-server,bluelml/core,pmattern/server,pollopolea/core,owncloud/core,owncloud/core,michaelletzgus/nextcloud-server,bluelml/core,pmattern/server,andreas-p/nextcloud-server,whitekiba/server,lrytz/core,whitekiba/server,pixelipo/server,endsguy/server,owncloud/core,pollopolea/core,pmattern/server,Ardinis/server,michaelletzgus/nextcloud-server,sharidas/core,pollopolea/core,pollopolea/core,xx621998xx/server,cernbox/core,cernbox/core,sharidas/core,xx621998xx/server,andreas-p/nextcloud-server,IljaN/core,andreas-p/nextcloud-server,jbicha/server,Ardinis/server,IljaN/core,whitekiba/server,andreas-p/nextcloud-server,pmattern/server,jbicha/server,nextcloud/server,owncloud/core,jbicha/server,pixelipo/server,IljaN/core,jbicha/server,endsguy/server,pollopolea/core,cernbox/core,xx621998xx/server,cernbox/core,sharidas/core,xx621998xx/server,bluelml/core,whitekiba/server,endsguy/server,lrytz/core,xx621998xx/server,jbicha/server,Ardinis/server,endsguy/server,lrytz/core,sharidas/core,pixelipo/server,bluelml/core