Return a proper error when method is not supported
Return a proper error when method is not supported

eevans/restbase,gwicke/restbase,Pchelolo/restbase,Krenair/restbase,wikimedia/mediawiki-services-restbase,cscott/restbase,wikimedia/restbase,milimetric/restbase,Krenair/restbase,d00rman/restbase,milimetric/restbase,wikimedia/mediawiki-services-restbase,d00rman/restbase,inverno/restbase,physikerwelt/restbase,wikimedia/hyperswitch,eevans/restbase,physikerwelt/restbase,inverno/restbase,hardikj/restbase,cscott/restbase,Pchelolo/restbase,wikimedia/restbase,hardikj/restbase,gwicke/restbase