Some shells (e.g. dash) do not support the source built-in. This
replaces it with the dot operator.
[ YOCTO #9535 ]
(From OE-Core rev: eef010bd91933d0c4b917d12e5716aa7e16b7307)
Signed-off-by: Stephano Cetola <stephano.cetola@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>