Use correct Parsoid v3 path for POST of pagebundle.
Use correct Parsoid v3 path for POST of pagebundle.

Change-Id: Id5208e4e1c7ffa9eeb93e9e4158129c6ed837975

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