udev: create /var/volatile/tmp to avoid dead link

If it's not first boot, /tmp has already been symlinked to /var/volatile/tmp.
But the udev service starts before populate-volatile.sh starts. This leads to
a dead link at /tmp. As a result, trying to create any file under /tmp will
fail.

If a USB is plugged in before the populate-volatile.sh script starts, the
/tmp/.automount-$name file will not be created correctly. As a result, when
the USB is unplugged, the /media/$name directory is not removed.

So we create /var/volatile/tmp directory in the udev script to avoid this dead
link problem.

[YOCTO #3404]

(From OE-Core master rev: 2f93c8466ca146c965585ea38210ddb5fb5754bd)

(From OE-Core rev: 78d44b0025a2fc117b67f8128385d0387955f01c)

Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/udev/udev/init

@@ -51,6 +51,7 @@ case "$1" in
     [ -e /dev/shm ] || mkdir -m 1777 /dev/shm
     mount -a -t tmpfs 2>/dev/null
     mkdir -p /var/volatile/run
+    mkdir -p /var/volatile/tmp
 
     # cache handling
     if [ "$DEVCACHE" != "" ]; then