Removal of the tool "mysql_zap"

MariaDB 10.1 still ships the tool "mysql_zap.sh" on the "scripts/" directory.
This tool basically does what the "pkill" tool does with the "-f" switch : killing processes whose name match a certain string.

The way the script match the processes it needs to kill isnt clean (using the output of a "ps" command), it outputs an stty error message when executed, doesnt output any warning after trying to kill processes the user doesnt own and waits at least 2 seconds after each kills which renders it unpractical.

The script doesnt seems to be called at any point on the MariaDB sources, doesnt do any MariaDB related job and is most probably not used anymore.