kmsplayerendpoint: Force caps negotiation in appsrc using the fixed caps set in appsink through event caps
kmsplayerendpoint: Force caps negotiation in appsrc using the fixed caps set in appsink through event caps

Change-Id: I1e1dad7ed2fdbdf4e36173377dcc6611ca9f9527

TribeMedia/kms-elements,TribeMedia/kms-elements,Kurento/kms-elements,shelsonjava/kms-elements,TribeMedia/kms-elements,shelsonjava/kms-elements,shelsonjava/kms-elements,Kurento/kms-elements,Kurento/kms-elements