image.bbclass: Fix locking so multiple image targets work

git-svn-id: https://svn.o-hand.com/repos/poky/trunk@4491 311d38ba-8fff-0310-9ca6-ca027cbcb966

meta/classes/image.bbclass

@@ -68,6 +68,7 @@ LINGUAS_INSTALL = "${@" ".join(map(lambda s: "locale-base-%s" % s, bb.data.getVa
 
 do_rootfs[nostamp] = "1"
 do_rootfs[dirs] = "${TOPDIR}"
+do_rootfs[lockfiles] = "${IMAGE_ROOTFS}.lock"
 do_build[nostamp] = "1"
 
 # Must call real_do_rootfs() from inside here, rather than as a separate