The "no dependencies" task case was not being correctly considered in this
code and seemed to be the cause of occasionaly task hash mismatch errors
that were being seen as the dependencies were never accounted for properly.
(Bitbake rev: 608b9f821539de813bfbd9e65950dbc56a274bc2)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>