WL#1477: Better mysql.server restart command

Affects: Server-4.1   —   Status: Un-Assigned   —   Priority: Medium

Recode mysql.server.sh to not use $0 for restart.  This doesn't always work as
the script makes a 'cd $basedir' before.

It's better to move the case to it's own function and let 'reset' call this
function with start and stop arguments.