image: Run do_rootfs_wicenv after do_image

do_image can modify the content of the rootfs directory so we need to run
do_rootfs_wicenv after do_image compeltes or the command can fail.

(From OE-Core rev: 8f5429b5e543e122072a51b518cc137dfc8ec442)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/image.bbclass

@@ -275,7 +275,7 @@ python do_rootfs_wicenv () {
             if value:
                 envf.write('%s="%s"\n' % (var, value.strip()))
 }
-addtask do_rootfs_wicenv after do_rootfs before do_image_wic do_image_complete
+addtask do_rootfs_wicenv after do_image before do_image_wic do_image_complete
 do_rootfs_wicenv[vardeps] += "${WICVARS}"
 do_rootfs_wicenv[prefuncs] = 'set_image_size'