Fix playerendpoint tests to use state-changed signal to change state
Fix playerendpoint tests to use state-changed signal to change state

Change-Id: Ibb61cc72200147ce5ac4c6966fec4a8e62af7f89

Kurento/kms-core,KurentoLegacy/gst-kurento-plugins,TribeMedia/kms-core,Kurento/kms-core,KurentoLegacy/gst-kurento-plugins,Kurento/kms-core,ESTOS/kms-core,KurentoLegacy/gst-kurento-plugins,shelsonjava/kms-core,shelsonjava/kms-core,TribeMedia/kms-core,TribeMedia/kms-core,ESTOS/kms-core,ESTOS/kms-core,Kurento/kms-core,ESTOS/kms-core,TribeMedia/kms-core,KurentoLegacy/gst-kurento-plugins,shelsonjava/kms-core,shelsonjava/kms-core