basetransform: optimize default acceptcaps implementation
basetransform: optimize default acceptcaps implementation

Pass the fixed caps we're asked to accept as a filter for the caps
query, so we don't get a fully-expanded set of caps back (which we don't
need and can take a lot of time for intersection).

This reduces the time for camerabin to produce a second frame on a
logitech C910 camera from around 52 seconds to a bit less then 16
seconds on my system.

https://bugzilla.gnome.org/show_bug.cgi?id=702632

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