kmswebrtcendpoint: throw certtool error exit to /dev/null
kmswebrtcendpoint: throw certtool error exit to /dev/null

Change-Id: I8bf2e96651317d85ec1595a31f939cc71df4ab1e

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