fix error in linux makefile for some shells

R=borenet@google.com
TBR=borenet@google.com
NOTRY=true

Author: halcanary@google.com

Review URL: https://codereview.chromium.org/196823007

git-svn-id: http://skia.googlecode.com/svn/trunk@13882 2bbb7eff-a529-9590-31e7-b0007b416f81

platform_tools/barelinux/bin/barelinux_make

@@ -34,7 +34,6 @@ EOF
 #  Coverage, Debug, Release, or Release_Developer
 BUILD_TYPE='Debug'
 
-unset OPTIND
 while getopts ":c:x:o:t:h" opt ; do
     case $opt in
         c)  export CC="$OPTARG" ;;