Build: make repopick.py executable

Change-Id: Ide52d3819d8dac37f8e300f96f8efcbbf993b866
repopick: fix broken pipe error from "repo list"

  * the subprocess running "repo list" was not closed cleanly
    if the branch was found

Change-Id: Ie659966f3a670b25ab076a8dc723c4235760d04e
repopick: skip a cherry pick if its already been merged

* override this behavior with the -f argument

Change-Id: I280b4945344e7483a192d1c9769c42b8fd2a2aef
Merge remote-tracking branch 'buildPA/jb43' into jb43