agnosticbin: Fix memory leak

Change-Id: Iacf86d4460ee2e88818f0ce2ef11cc252a03069d
valgrind: Add suppresion for gst_static_pad_template_get

Is has a memory leak at least on gstreamer 1.3

Change-Id: I8f9798baabf7e7759ddcf1cbacaf72fa87d89ca5