am 32bc0787: Add use of sentinel in BOOTCLASSPATH entries during preopt.

Merge commit '32bc0787307ba57e92fa74c52da550e2ca22af7f' into gingerbread-plus-aosp

* commit '32bc0787307ba57e92fa74c52da550e2ca22af7f':
  Add use of sentinel in BOOTCLASSPATH entries during preopt.