- fix setting of niceness level

support-files/mysql.server.sh
     - applied some fixes from 4.0 mysql.server script
     - fix my.cnf parsing


scripts/safe_mysqld.sh:
   - fix setting of niceness level, if one adds "renice -20 $$" to safe_mysqld
     as hinted in the manual (which could result in NOHUP_NICENESS having a
     value of "-15" and hence there would be one dash too much)
support-files/mysql.server.sh:
   - applied some fixes from 4.0 mysql.server script
   - fix to actually parse the documented section ([mysql.server] not
     [mysql_server]) in my.cnf on startup