am 5249ad03: docs: add "boot completed" broadcast to list of DO NOTs for installing on external storage bug: 3088494

Merge commit '5249ad03454301744374d04e04b38aaad3b01530' into gingerbread

* commit '5249ad03454301744374d04e04b38aaad3b01530':
  docs: add "boot completed" broadcast to list of DO NOTs for installing on external storage