wic/engine: use 'linux-swap' for swap file system
[YOCTO #13312]
see https://bugzilla.yoctoproject.org/show_bug.cgi?id=13312
wic/engine.Disk._get_part_image was looking at variable fstypes for
supported fstype which is 'swap' but image build with 'linux-swap'.
supported fstype should be 'linux-swap'.
Signed-off-by: Chee Yang Lee <chee.yang.lee@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit
7e6da22fe4faf841bcec02e55f376b4dae04d6a8)
Signed-off-by: Armin Kuster <akuster808@gmail.com>
