Move toolchain setup into a function in android_setup.sh

Addresses https://code.google.com/p/skia/issues/detail?id=1486

R=djsollen@google.com

Review URL: https://codereview.chromium.org/22339008

git-svn-id: http://skia.googlecode.com/svn/trunk@10563 2bbb7eff-a529-9590-31e7-b0007b416f81
1 file changed