get effective username after webdav login, fixes oc-2108
get effective username after webdav login, fixes oc-2108

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