servicemp3: fix regression from 29c3389dfadd68f...

This commit caused gstreamer to not return shoutcast stream
metadata to the application (shoutcast, NETcaster etc).

Signed-off-by: Erik Slagter <erik@openpli.org>
Merge branch 'master' of git://git.code.sf.net/p/openpli/enigma2
merge