Exception: TypeError: boolean accepts a string, not '<class 'bool'>
is a bit annoying if you pass in True/False. Tweak the function
to make it forgive that situation.
(From OE-Core rev: 147f5a665fe5073027d92e4acac631f15f08f79f)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>