Provide better feedback to the user when unable to find MySQL files

usually caused by a bad basedir setting.


support-files/mysql.server.sh:
  Be more verbose in error message.

support-files/mysql.server.sh

@@ -311,7 +311,7 @@ case "$mode" in
       fi
       exit $return_value
     else
-      log_failure_msg "Couldn't find MySQL manager or server"
+      log_failure_msg "Couldn't find MySQL manager ($manager) or server ($bindir/mysqld_safe)"
     fi
     ;;