VP9-SVC: Bugfix to allow skipping lower layer(s) encoding.
VP9-SVC: Bugfix to allow skipping lower layer(s) encoding.

The setting of svc->spatial_layer_to_encode was missing
in VP9E_SET_SVC_LAYER_ID.

Change-Id: I015b1a64adb9ef2644d6477a02d9d9364c8462b9

ittiamvpx/libvpx-1,Topopiccione/libvpx,smarter/aom,openpeer/libvpx_new,GrokImageCompression/aom,ShiftMediaProject/libvpx,shacklettbp/aom,mwgoldsmith/vpx,mwgoldsmith/libvpx,jmvalin/aom,mwgoldsmith/libvpx,webmproject/libvpx,luctrudeau/aom,GrokImageCompression/aom,mbebenita/aom,webmproject/libvpx,luctrudeau/aom,ShiftMediaProject/libvpx,ittiamvpx/libvpx-1,ittiamvpx/libvpx-1,mbebenita/aom,thdav/aom,thdav/aom,smarter/aom,webmproject/libvpx,thdav/aom,mwgoldsmith/libvpx,smarter/aom,webmproject/libvpx,smarter/aom,luctrudeau/aom,ShiftMediaProject/libvpx,jmvalin/aom,webmproject/libvpx,shacklettbp/aom,shacklettbp/aom,mwgoldsmith/libvpx,ShiftMediaProject/libvpx,Topopiccione/libvpx,mwgoldsmith/vpx,smarter/aom,mwgoldsmith/libvpx,openpeer/libvpx_new,shacklettbp/aom,GrokImageCompression/aom,luctrudeau/aom,Topopiccione/libvpx,mwgoldsmith/libvpx,mbebenita/aom,openpeer/libvpx_new,mwgoldsmith/vpx,thdav/aom,mbebenita/aom,mbebenita/aom,jmvalin/aom,GrokImageCompression/aom,mwgoldsmith/vpx,ittiamvpx/libvpx-1,luctrudeau/aom,ittiamvpx/libvpx-1,mbebenita/aom,ShiftMediaProject/libvpx,mbebenita/aom,Topopiccione/libvpx,smarter/aom,webmproject/libvpx,jmvalin/aom,thdav/aom,openpeer/libvpx_new,mbebenita/aom,GrokImageCompression/aom,mwgoldsmith/vpx,GrokImageCompression/aom,luctrudeau/aom,mwgoldsmith/vpx,mbebenita/aom,shacklettbp/aom,shacklettbp/aom,jmvalin/aom,Topopiccione/libvpx,jmvalin/aom,ittiamvpx/libvpx-1,Topopiccione/libvpx,openpeer/libvpx_new,openpeer/libvpx_new,thdav/aom