Removed unused deleteAll method on Common storage class
Removed unused deleteAll method on Common storage class

The "deleteAll" method on the Common storage class isn't used anywhere.
Also, it isn't defined on the Storage interface so this fix removes it
completely.

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