Update build-tools to ab/4524985 am: 7ec2be6859
am: 9dcd3c19ec

Change-Id: I40b2fbe7332a3ebdc445e63d06e329c972600d08
tree: 271daec82d4b433202a15012c003273a33dc7d1e
  1. common/
  2. darwin-x86/
  3. linux-x86/
  4. build-prebuilts.sh
  5. manifest.xml
  6. OWNERS