rtpdtmfsoundsource: Correctly check the presence of elements
rtpdtmfsoundsource: Correctly check the presence of elements

shadeslayer/farstream,shadeslayer/farstream,kakaroto/farstream,tieto/farstream,tieto/farstream,tieto/farstream,ahmedammar/skype_farsight2,kakaroto/farstream,pexip/farstream,pexip/farstream,ahmedammar/skype_farsight2,ahmedammar/skype_farsight2,tieto/farstream,kakaroto/farstream,kakaroto/farstream,shadeslayer/farstream,shadeslayer/farstream,pexip/farstream,tieto/farstream,ahmedammar/skype_farsight2,pexip/farstream