tests: gstutils: fix wrong description of test element
tests: gstutils: fix wrong description of test element

It is a fakesink with request pads, not a source

krichter722/gstreamer,centricular/gstreamer,jpxiong/gstreamer,krichter722/gstreamer,shelsonjava/gstreamer,centricular/gstreamer,krichter722/gstreamer,centricular/gstreamer,shelsonjava/gstreamer,StreamUtils/gstreamer,jpxiong/gstreamer,centricular/gstreamer,krichter722/gstreamer,centricular/gstreamer,jpxiong/gstreamer,jpxiong/gstreamer,StreamUtils/gstreamer,StreamUtils/gstreamer,StreamUtils/gstreamer,StreamUtils/gstreamer,jpxiong/gstreamer,shelsonjava/gstreamer,shelsonjava/gstreamer,shelsonjava/gstreamer,krichter722/gstreamer