Fix column width of mtime column
Fix column width of mtime column

* in some translations (e.g. german) the header of this column otherwise
  got truncated
  "Zeitpunkt der Freigabe" vs "Zeitpunkt der Freig"

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