Statistics.cpp: Fix collection of measures from a GstStructure
Statistics.cpp: Fix collection of measures from a GstStructure

Change-Id: If513df77356b888c431b4d30b5fcdadcfec4b0f0

Kurento/kms-core,TribeMedia/kms-core,Kurento/kms-core,shelsonjava/kms-core,ESTOS/kms-core,Kurento/kms-core,Kurento/kms-core,ESTOS/kms-core,TribeMedia/kms-core,shelsonjava/kms-core,TribeMedia/kms-core,shelsonjava/kms-core,TribeMedia/kms-core,shelsonjava/kms-core,ESTOS/kms-core,ESTOS/kms-core