MDEV-15050 scripts: mysql_install_db.{sh|pl}, mysqld_multi - mysqld is in @sbindir@

Closes #551

scripts/mysql_install_db.pl.in

@@ -326,7 +326,7 @@ else
   $opt->{basedir} = '@prefix@';
   $bindir         = '@bindir@';
   $extra_bindir   = $bindir;
-  $mysqld         = '@libexecdir@/mysqld';
+  $mysqld         = '@sbindir@/mysqld';
   $pkgdatadir     = '@pkgdatadir@';
   $scriptdir      = '@scriptdir@';
 }

scripts/mysql_install_db.sh

@@ -311,7 +311,7 @@ else
   basedir="@prefix@"
   bindir="@bindir@"
   resolveip="$bindir/resolveip"
-  mysqld="@libexecdir@/mysqld"
+  mysqld="@sbindir@/mysqld"
   pkgdatadir="@pkgdatadir@"
 fi
 

scripts/mysqld_multi.sh

@@ -30,7 +30,7 @@ $opt_example       = 0;
 $opt_help          = 0;
 $opt_log           = undef();
 $opt_mysqladmin    = "@bindir@/mysqladmin";
-$opt_mysqld        = "@libexecdir@/mysqld";
+$opt_mysqld        = "@sbindir@/mysqld";
 $opt_no_log        = 0;
 $opt_password      = undef();
 $opt_tcp_ip        = 0;