enc/vp8l: fix uninitialized variable warning
enc/vp8l: fix uninitialized variable warning

histogram_image_size could be unset if the code branches to the 'Error'
label.

Change-Id: I690b20f86372f19a47d159c2bec8fbf49553f0d5

rxl194/libwebp,abwiz0086/webm.libwebp,matanbs/webm.libwebp,zofuthan/libwebp,comoyo/gonzo-libwebp,kim42083/webm.libwebp,ya7lelkom/libwebp,Distrotech/libwebp,abwiz0086/webm.libwebp,dumganhar/libwebp,appunite/libwebp,Maria1099/webm.libwebp,jacklicn/libwebp,PKRoma/libwebp,dumganhar/libwebp,webmproject/libwebp,yohunl/libwebp,gshORTON/webm.libwebp,altogother/webm.libwebp,redengineer/libwebp,imazen/libwebp,PKRoma/libwebp,iniwf/webm.libwebp,altogother/webm.libwebp,Suvarna1488/webm.libwebp,jiehu5114/libwebp,yohunl/libwebp,PKRoma/libwebp,jacklicn/libwebp,redengineer/libwebp,jiehu5114/libwebp,redengineer/libwebp,reimaginemedia/webm.libwebp,appunite/libwebp,matanbs/webm.libwebp,kleopatra999/webm.libwebp,Tekserve/libwebp,appunite/libwebp,Maria1099/webm.libwebp,PKRoma/libwebp,ttyangf/libwebp,keane83/BLE_IM,ericmckean/webm.libwebp,jiehu5114/libwebp,comoyo/gonzo-libwebp,reimaginemedia/webm.libwebp,kim42083/webm.libwebp,reimaginemedia/webm.libwebp,matanbs/webm.libwebp,Acidburn0zzz/webm.libwebp,iniwf/webm.libwebp,iniwf/webm.libwebp,Distrotech/libwebp,Tekserve/libwebp,imazen/libwebp,kleopatra999/webm.libwebp,altogother/webm.libwebp,abwiz0086/webm.libwebp,webmproject/libwebp,zofuthan/libwebp,yohunl/libwebp,iniwf/webm.libwebp,imazen/libwebp,jiehu5114/libwebp,appunite/libwebp,zofuthan/libwebp,PKRoma/libwebp,keane83/BLE_IM,ya7lelkom/libwebp,gshORTON/webm.libwebp,ericmckean/webm.libwebp,reimaginemedia/webm.libwebp,yohunl/libwebp,gshORTON/webm.libwebp,ericmckean/webm.libwebp,comoyo/gonzo-libwebp,Maria1099/webm.libwebp,yohunl/libwebp,dumganhar/libwebp,Acidburn0zzz/webm.libwebp,kleopatra999/webm.libwebp,Tekserve/libwebp,jacklicn/libwebp,keane83/BLE_IM,jacklicn/libwebp,cysp/libwebp,comoyo/gonzo-libwebp,comoyo/gonzo-libwebp,ericmckean/webm.libwebp,keane83/BLE_IM,kalli123/webm.libwebp,jacklicn/libwebp,cysp/libwebp,altogother/webm.libwebp,Maria1099/webm.libwebp,webmproject/libwebp,gshORTON/webm.libwebp,rxl194/libwebp,webmproject/libwebp,Tekserve/libwebp,Suvarna1488/webm.libwebp,comoyo/gonzo-libwebp,ttyangf/libwebp,ya7lelkom/libwebp,redengineer/libwebp,ya7lelkom/libwebp,redengineer/libwebp,zofuthan/libwebp,ya7lelkom/libwebp,comoyo/gonzo-libwebp,kalli123/webm.libwebp,cysp/libwebp,Suvarna1488/webm.libwebp,appunite/libwebp,kalli123/webm.libwebp,Acidburn0zzz/webm.libwebp,matanbs/webm.libwebp,Aexyn/libwebp,imazen/libwebp,ericmckean/webm.libwebp,cysp/libwebp,kalli123/webm.libwebp,Aexyn/libwebp,Suvarna1488/webm.libwebp,ttyangf/libwebp,Aexyn/libwebp,Suvarna1488/webm.libwebp,rxl194/libwebp,ttyangf/libwebp,kim42083/webm.libwebp,Maria1099/webm.libwebp,kim42083/webm.libwebp,ttyangf/libwebp,Aexyn/libwebp,kleopatra999/webm.libwebp,PKRoma/libwebp,rxl194/libwebp,webmproject/libwebp,abwiz0086/webm.libwebp,matanbs/webm.libwebp,iniwf/webm.libwebp,appunite/libwebp,Distrotech/libwebp,altogother/webm.libwebp,Acidburn0zzz/webm.libwebp,jiehu5114/libwebp,zofuthan/libwebp,Aexyn/libwebp,kim42083/webm.libwebp,Acidburn0zzz/webm.libwebp,imazen/libwebp,reimaginemedia/webm.libwebp,kalli123/webm.libwebp,kleopatra999/webm.libwebp,abwiz0086/webm.libwebp,keane83/BLE_IM,rxl194/libwebp,gshORTON/webm.libwebp