fix warnings given by MDB2 if opendir is restricted by the host
fix warnings given by MDB2 if opendir is restricted by the host

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