Use tempfile.mkstemp to create a temporary file in the sstate dir and move it
into place after closing. The previous code would fail in the chmod() if two
users were running jobs that touched the same signature file.
(Bitbake rev: ff11e9ac5eba2d957917664a7b91b1277d8ad548)
Signed-off-by: Jeffrey C Honig <jeffrey.honig@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>