BUG#26148391 MYSQLD_PRE_SYSTEMD SCRIPT DOES NOT GET ERROR LOG FROM CUSTOM MY.CNF

Script searched for log-error only, however log_error is also
supported by mysqld, fixed by using regexp.

(cherry picked from commit 10819a832cccddf894ba32b6b39f739b16283433)

Author: trosten

scripts/systemd/mysqld_pre_systemd.in

@@ -43,7 +43,7 @@ install_db () {
 
     local instance=$1
     datadir=$(get_option mysqld datadir "/var/lib/mysql${instance:+-$instance}" $instance)
-    log=$(get_option mysqld log-error "/var/log/mysql${instance:+-$instance}.log" $instance)
+    log=$(get_option mysqld 'log[_-]error' "/var/log/mysql${instance:+-$instance}.log" $instance)
 
     # Restore log, dir, perms and SELinux contexts