The mechanism used to get the hash for a stamp file is split out so that
it can be overridden by derived classes
[YOCTO #13030]
(Bitbake rev: ce241534d19b2f1c51dbdb3b92419676d234e464)
Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>