ext/vorbis/vorbisdec.c: use explicit caps on the srcpad
ext/vorbis/vorbisdec.c: use explicit caps on the srcpad

Original commit message from CVS:
* ext/vorbis/vorbisdec.c: (gst_vorbis_dec_init):
use explicit caps on the srcpad
* ext/vorbis/vorbisdec.c: (vorbis_dec_chain):
properly error out if caps couldn't be set (fixes #142764)

fluendo/gst-plugins-ugly,GStreamer/gst-plugins-ugly,jahrome/gst-plugins-ugly,collects/gst-plugins-ugly,Kurento/gst-plugins-ugly,ahmedammar/platform_external_gst_plugins_ugly,fluendo/gst-plugins-ugly,GrokImageCompression/gst-plugins-ugly,Lachann/gst-plugins-ugly,freedesktop-unofficial-mirror/gstreamer__gst-plugins-ugly,fluendo/gst-plugins-ugly,matsu/gst-plugins-ugly,shelsonjava/gst-plugins-ugly,shelsonjava/gst-plugins-ugly,cablelabs/gst-plugins-ugly,knuesel/gst-plugins-ugly,Lachann/gst-plugins-ugly,Distrotech/gst-plugins-ugly,GStreamer/gst-plugins-ugly,ahmedammar/platform_external_gst_plugins_ugly,freedesktop-unofficial-mirror/gstreamer-sdk__gst-plugins-ugly,collects/gst-plugins-ugly,jpakkane/gstreamer-plugins-ugly,sebras/gst-plugins-ugly,PPCDroid/external-gst-plugins-ugly,StreamUtils/gst-plugins-ugly,StreamUtils/gst-plugins-ugly,GrokImageCompression/gst-plugins-ugly,ahmedammar/platform_external_gst_plugins_ugly,StreamUtils/gst-plugins-ugly,freedesktop-unofficial-mirror/gstreamer-sdk__gst-plugins-ugly,Distrotech/gst-plugins-ugly,alessandrod/gst-plugins-ugly,GStreamer/gst-plugins-ugly,krieger-od/gst-plugins-ugly,shelsonjava/gst-plugins-ugly,jpakkane/gstreamer-plugins-ugly,matsu/gst-plugins-ugly,jar1karp/gst-plugins-ugly,Kurento/gst-plugins-ugly,Distrotech/gst-plugins-ugly,reynaldo-samsung/gst-plugins-ugly,knuesel/gst-plugins-ugly,jahrome/gst-plugins-ugly,Kurento/gst-plugins-ugly,knuesel/gst-plugins-ugly,prajnashi/gst-plugins-ugly,jar1karp/gst-plugins-ugly,ylatuya/gst-plugins-ugly,reynaldo-samsung/gst-plugins-ugly,collects/gst-plugins-ugly,Lachann/gst-plugins-ugly,surround-io/gst-plugins-ugly,surround-io/gst-plugins-ugly,PPCDroid/external-gst-plugins-ugly,cablelabs/gst-plugins-ugly,jpakkane/gstreamer-plugins-ugly,alessandrod/gst-plugins-ugly,surround-io/gst-plugins-ugly,reynaldo-samsung/gst-plugins-ugly,prajnashi/gst-plugins-ugly,PPCDroid/external-gst-plugins-ugly,freedesktop-unofficial-mirror/gstreamer-sdk__gst-plugins-ugly,sebras/gst-plugins-ugly,freedesktop-unofficial-mirror/gstreamer__gst-plugins-ugly,matsu/gst-plugins-ugly,sebras/gst-plugins-ugly,collects/gst-plugins-ugly,ylatuya/gst-plugins-ugly,freedesktop-unofficial-mirror/gstreamer__gst-plugins-ugly,jahrome/gst-plugins-ugly,Distrotech/gst-plugins-ugly,alessandrod/gst-plugins-ugly,krieger-od/gst-plugins-ugly,krieger-od/gst-plugins-ugly,Distrotech/gst-plugins-ugly,cablelabs/gst-plugins-ugly,matsu/gst-plugins-ugly,GrokImageCompression/gst-plugins-ugly,krieger-od/gst-plugins-ugly,ylatuya/gst-plugins-ugly,jar1karp/gst-plugins-ugly,prajnashi/gst-plugins-ugly