Use mktemp instead of deprecated tempfile

This fixes the warning emitted during `/etc/init.d/mariadb restart`: WARNING: tempfile is deprecated; consider using mktemp instead.

Author: ottok

debian/additions/debian-start.inc.sh

@@ -15,7 +15,7 @@ function check_for_crashed_tables() {
 
  # Checking for $? is unreliable so the size of the output is checked.
  # Some table handlers like HEAP do not support CHECK TABLE.
- tempfile=`tempfile`
+ tempfile=$(mktemp)
 
  # We have to use xargs in this case, because a for loop barfs on the
  # spaces in the thing to be looped over.