variance_test: fix build w/--disable-vp8-encoder
variance_test: fix build w/--disable-vp8-encoder

s/CONFIG_VP8\b/CONFIG_VP8_ENCODER/

Change-Id: I616aace9cf8f18d7e83f00f7aef3b8a26fc4c17b

GrokImageCompression/aom,mbebenita/aom,shacklettbp/aom,ittiamvpx/libvpx-1,Topopiccione/libvpx,shacklettbp/aom,zofuthan/libvpx,openpeer/libvpx_new,shacklettbp/aom,GrokImageCompression/aom,jmvalin/aom,running770/libvpx,shyamalschandra/libvpx,goodleixiao/vpx,zofuthan/libvpx,liqianggao/libvpx,thdav/aom,stewnorriss/libvpx,shyamalschandra/libvpx,mwgoldsmith/vpx,smarter/aom,felipebetancur/libvpx,liqianggao/libvpx,jmvalin/aom,thdav/aom,GrokImageCompression/aom,luctrudeau/aom,shyamalschandra/libvpx,luctrudeau/aom,smarter/aom,liqianggao/libvpx,thdav/aom,thdav/aom,smarter/aom,VTCSecureLLC/libvpx,GrokImageCompression/aom,shyamalschandra/libvpx,liqianggao/libvpx,jmvalin/aom,openpeer/libvpx_new,running770/libvpx,mwgoldsmith/libvpx,goodleixiao/vpx,luctrudeau/aom,VTCSecureLLC/libvpx,VTCSecureLLC/libvpx,jmvalin/aom,thdav/aom,webmproject/libvpx,shacklettbp/aom,ittiamvpx/libvpx-1,mbebenita/aom,felipebetancur/libvpx,liqianggao/libvpx,goodleixiao/vpx,shacklettbp/aom,felipebetancur/libvpx,zofuthan/libvpx,zofuthan/libvpx,ShiftMediaProject/libvpx,mbebenita/aom,smarter/aom,stewnorriss/libvpx,thdav/aom,ittiamvpx/libvpx-1,goodleixiao/vpx,ShiftMediaProject/libvpx,smarter/aom,luctrudeau/aom,Topopiccione/libvpx,ittiamvpx/libvpx-1,mwgoldsmith/vpx,webmproject/libvpx,mwgoldsmith/libvpx,mwgoldsmith/libvpx,ShiftMediaProject/libvpx,mwgoldsmith/vpx,ShiftMediaProject/libvpx,jmvalin/aom,luctrudeau/aom,running770/libvpx,VTCSecureLLC/libvpx,mwgoldsmith/vpx,mbebenita/aom,openpeer/libvpx_new,shacklettbp/aom,openpeer/libvpx_new,Topopiccione/libvpx,mbebenita/aom,mwgoldsmith/libvpx,mwgoldsmith/vpx,webmproject/libvpx,VTCSecureLLC/libvpx,openpeer/libvpx_new,running770/libvpx,liqianggao/libvpx,GrokImageCompression/aom,goodleixiao/vpx,felipebetancur/libvpx,mbebenita/aom,webmproject/libvpx,mbebenita/aom,felipebetancur/libvpx,webmproject/libvpx,openpeer/libvpx_new,mbebenita/aom,ittiamvpx/libvpx-1,Topopiccione/libvpx,zofuthan/libvpx,Topopiccione/libvpx,stewnorriss/libvpx,mwgoldsmith/libvpx,ittiamvpx/libvpx-1,zofuthan/libvpx,stewnorriss/libvpx,stewnorriss/libvpx,luctrudeau/aom,smarter/aom,running770/libvpx,GrokImageCompression/aom,felipebetancur/libvpx,goodleixiao/vpx,shyamalschandra/libvpx,running770/libvpx,ShiftMediaProject/libvpx,mwgoldsmith/libvpx,webmproject/libvpx,jmvalin/aom,VTCSecureLLC/libvpx,Topopiccione/libvpx,shyamalschandra/libvpx,mwgoldsmith/vpx,stewnorriss/libvpx,mbebenita/aom