Add a umask context manager which can be used to temporarily change the
umask in a 'with' block.
(Bitbake rev: 6ca998054e422da72c7906d3ec4f204d88c32ee0)
Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Steve Sakoman <steve@sakoman.com>