pad: only serialized events can't pass after EOS
pad: only serialized events can't pass after EOS

Only serialized events can't be sent on pads that are EOS. Otherwise a seek
event would be refused as well.

Fixes https://bugzilla.gnome.org/show_bug.cgi?id=677520

cablelabs/gstreamer,collects/gstreamer,jpxiong/gstreamer,krichter722/gstreamer,krieger-od/gstreamer,jpakkane/gstreamer,ensonic/gstreamer,krieger-od/gstreamer,lubosz/gstreamer,lubosz/gstreamer,surround-io/gstreamer,collects/gstreamer,jpakkane/gstreamer,shelsonjava/gstreamer,StreamUtils/gstreamer,Lachann/gstreamer,cablelabs/gstreamer,shelsonjava/gstreamer,cfoch/gstreamer,jpakkane/gstreamer,cfoch/gstreamer,Lachann/gstreamer,jpxiong/gstreamer,centricular/gstreamer,shelsonjava/gstreamer,krieger-od/gstreamer,collects/gstreamer,jpxiong/gstreamer,centricular/gstreamer,StreamUtils/gstreamer,cablelabs/gstreamer,jpakkane/gstreamer,ensonic/gstreamer,lubosz/gstreamer,surround-io/gstreamer,surround-io/gstreamer,collects/gstreamer,justinjoy/gstreamer,surround-io/gstreamer,cfoch/gstreamer,mparis/gstreamer,ensonic/gstreamer,mparis/gstreamer,jpxiong/gstreamer,centricular/gstreamer,lovebug356/gstreamer,cablelabs/gstreamer,shelsonjava/gstreamer,lovebug356/gstreamer,lubosz/gstreamer,cfoch/gstreamer,krichter722/gstreamer,cablelabs/gstreamer,lovebug356/gstreamer,justinjoy/gstreamer,lubosz/gstreamer,krichter722/gstreamer,jpxiong/gstreamer,centricular/gstreamer,centricular/gstreamer,ensonic/gstreamer,jpakkane/gstreamer,krieger-od/gstreamer,cfoch/gstreamer,mparis/gstreamer,collects/gstreamer,justinjoy/gstreamer,ensonic/gstreamer,Lachann/gstreamer,krichter722/gstreamer,StreamUtils/gstreamer,Lachann/gstreamer,justinjoy/gstreamer,StreamUtils/gstreamer,krieger-od/gstreamer,krichter722/gstreamer,Lachann/gstreamer,lovebug356/gstreamer,surround-io/gstreamer,mparis/gstreamer,lovebug356/gstreamer,StreamUtils/gstreamer,mparis/gstreamer,shelsonjava/gstreamer,justinjoy/gstreamer