Fix the variable naming in encode_block
Fix the variable naming in encode_block

The term x represents macroblock pointer across encode_block. Change
the two local variable names to avoid confusion.

Change-Id: Ic732e73023525d673c0a678ed2708ac1edf5a3f9

pcwalton/libvpx,Topopiccione/libvpx,felipebetancur/libvpx,pcwalton/libvpx,lyx2014/libvpx_c,Suvarna1488/webm.libvpx,sanyaade-teachings/libvpx,Topopiccione/libvpx,ShiftMediaProject/libvpx,sanyaade-teachings/libvpx,Laknot/libvpx,VTCSecureLLC/libvpx,shyamalschandra/libvpx,running770/libvpx,iniwf/webm.libvpx,Laknot/libvpx,jacklicn/webm.libvpx,gshORTON/webm.libvpx,reimaginemedia/webm.libvpx,luctrudeau/aom,zofuthan/libvpx,mbebenita/aom,Laknot/libvpx,stewnorriss/libvpx,abwiz0086/webm.libvpx,kim42083/webm.libvpx,goodleixiao/vpx,mbebenita/aom,felipebetancur/libvpx,reimaginemedia/webm.libvpx,mbebenita/aom,kalli123/webm.libvpx,abwiz0086/webm.libvpx,webmproject/libvpx,Distrotech/libvpx,sanyaade-teachings/libvpx,charup/https---github.com-webmproject-libvpx-,charup/https---github.com-webmproject-libvpx-,Suvarna1488/webm.libvpx,openpeer/libvpx_new,matanbs/vp982,lyx2014/libvpx_c,Laknot/libvpx,reimaginemedia/webm.libvpx,iniwf/webm.libvpx,felipebetancur/libvpx,luctrudeau/aom,ittiamvpx/libvpx-1,stewnorriss/libvpx,turbulenz/libvpx,shyamalschandra/libvpx,turbulenz/libvpx,running770/libvpx,VTCSecureLLC/libvpx,shareefalis/libvpx,VTCSecureLLC/libvpx,Laknot/libvpx,hsueceumd/test_hui,thdav/aom,turbulenz/libvpx,luctrudeau/aom,smarter/aom,ittiamvpx/libvpx,liqianggao/libvpx,Distrotech/libvpx,liqianggao/libvpx,altogother/webm.libvpx,sanyaade-teachings/libvpx,shareefalis/libvpx,Acidburn0zzz/webm.libvpx,kim42083/webm.libvpx,charup/https---github.com-webmproject-libvpx-,ShiftMediaProject/libvpx,gshORTON/webm.libvpx,Maria1099/webm.libvpx,liqianggao/libvpx,kim42083/webm.libvpx,GrokImageCompression/aom,matanbs/webm.libvpx,thdav/aom,gshORTON/webm.libvpx,pcwalton/libvpx,WebRTC-Labs/libvpx,turbulenz/libvpx,Acidburn0zzz/webm.libvpx,Topopiccione/libvpx,shacklettbp/aom,goodleixiao/vpx,mwgoldsmith/vpx,Laknot/libvpx,abwiz0086/webm.libvpx,kleopatra999/webm.libvpx,webmproject/libvpx,Distrotech/libvpx,pcwalton/libvpx,shareefalis/libvpx,goodleixiao/vpx,ittiamvpx/libvpx,matanbs/vp982,GrokImageCompression/aom,WebRTC-Labs/libvpx,luctrudeau/aom,turbulenz/libvpx,Distrotech/libvpx,kalli123/webm.libvpx,jmvalin/aom,shyamalschandra/libvpx,gshORTON/webm.libvpx,zofuthan/libvpx,ittiamvpx/libvpx-1,jacklicn/webm.libvpx,matanbs/webm.libvpx,jdm/libvpx,altogother/webm.libvpx,Suvarna1488/webm.libvpx,matanbs/webm.libvpx,zofuthan/libvpx,ShiftMediaProject/libvpx,kalli123/webm.libvpx,zofuthan/libvpx,jacklicn/webm.libvpx,jmvalin/aom,GrokImageCompression/aom,mwgoldsmith/libvpx,smarter/aom,altogother/webm.libvpx,shacklettbp/aom,WebRTC-Labs/libvpx,openpeer/libvpx_new,turbulenz/libvpx,Topopiccione/libvpx,gshORTON/webm.libvpx,lyx2014/libvpx_c,hsueceumd/test_hui,hsueceumd/test_hui,shyamalschandra/libvpx,WebRTC-Labs/libvpx,mbebenita/aom,luctrudeau/aom,mwgoldsmith/libvpx,lyx2014/libvpx_c,stewnorriss/libvpx,kalli123/webm.libvpx,n4t/libvpx,felipebetancur/libvpx,mbebenita/aom,mwgoldsmith/libvpx,smarter/aom,iniwf/webm.libvpx,ittiamvpx/libvpx,reimaginemedia/webm.libvpx,matanbs/vp982,VTCSecureLLC/libvpx,ittiamvpx/libvpx,thdav/aom,abwiz0086/webm.libvpx,turbulenz/libvpx,liqianggao/libvpx,mbebenita/aom,lyx2014/libvpx_c,hsueceumd/test_hui,altogother/webm.libvpx,iniwf/webm.libvpx,jdm/libvpx,Acidburn0zzz/webm.libvpx,WebRTC-Labs/libvpx,jacklicn/webm.libvpx,mwgoldsmith/vpx,Suvarna1488/webm.libvpx,openpeer/libvpx_new,ittiamvpx/libvpx-1,Maria1099/webm.libvpx,charup/https---github.com-webmproject-libvpx-,shareefalis/libvpx,jacklicn/webm.libvpx,kleopatra999/webm.libvpx,kalli123/webm.libvpx,matanbs/vp982,liqianggao/libvpx,abwiz0086/webm.libvpx,matanbs/vp982,stewnorriss/libvpx,Acidburn0zzz/webm.libvpx,felipebetancur/libvpx,Topopiccione/libvpx,n4t/libvpx,kalli123/webm.libvpx,ShiftMediaProject/libvpx,mbebenita/aom,turbulenz/libvpx,thdav/aom,Distrotech/libvpx,webmproject/libvpx,matanbs/webm.libvpx,altogother/webm.libvpx,liqianggao/libvpx,openpeer/libvpx_new,shyamalschandra/libvpx,n4t/libvpx,Maria1099/webm.libvpx,lyx2014/libvpx_c,shacklettbp/aom,charup/https---github.com-webmproject-libvpx-,Acidburn0zzz/webm.libvpx,iniwf/webm.libvpx,charup/https---github.com-webmproject-libvpx-,Topopiccione/libvpx,shacklettbp/aom,GrokImageCompression/aom,pcwalton/libvpx,gshORTON/webm.libvpx,kleopatra999/webm.libvpx,ittiamvpx/libvpx-1,mwgoldsmith/libvpx,Suvarna1488/webm.libvpx,Suvarna1488/webm.libvpx,mbebenita/aom,reimaginemedia/webm.libvpx,n4t/libvpx,hsueceumd/test_hui,running770/libvpx,smarter/aom,ittiamvpx/libvpx-1,jdm/libvpx,Maria1099/webm.libvpx,goodleixiao/vpx,ShiftMediaProject/libvpx,kim42083/webm.libvpx,kim42083/webm.libvpx,jmvalin/aom,mwgoldsmith/libvpx,VTCSecureLLC/libvpx,thdav/aom,Maria1099/webm.libvpx,hsueceumd/test_hui,zofuthan/libvpx,jdm/libvpx,ittiamvpx/libvpx,jdm/libvpx,GrokImageCompression/aom,stewnorriss/libvpx,abwiz0086/webm.libvpx,webmproject/libvpx,webmproject/libvpx,altogother/webm.libvpx,luctrudeau/aom,kim42083/webm.libvpx,openpeer/libvpx_new,goodleixiao/vpx,shyamalschandra/libvpx,shacklettbp/aom,mwgoldsmith/vpx,Maria1099/webm.libvpx,reimaginemedia/webm.libvpx,shareefalis/libvpx,kleopatra999/webm.libvpx,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