include/image.mk: /tmp should have mode 1777

On the off chance that the root filesystem's /tmp is used directly as a
temporary directory instead of having a tmpfs mounted over it, it should have
the sticky bit set.

Signed-off-by: Mark Mentovai <mark@moxienet.com>

SVN-Revision: 32572

include/image.mk

@@ -146,7 +146,7 @@ define Image/mkfs/prepare/default
 	- $(FIND) $(TARGET_DIR) -type f -perm +0100 -print0 | $(XARGS) -0 chmod u+rwx,g+rx,o+rx
 	- $(FIND) $(TARGET_DIR) -type d -print0 | $(XARGS) -0 chmod u+rwx,g+rx,o+rx
 	$(INSTALL_DIR) $(TARGET_DIR)/tmp
-	chmod 0777 $(TARGET_DIR)/tmp
+	chmod 1777 $(TARGET_DIR)/tmp
 endef
 
 define Image/mkfs/prepare