Merge branch '10.1' into 10.2

Revert commit db0917f68f, because the fix for MDEV-12696
is coming from 5.5 and 10.1 in this merge.

support-files/mysql.server.sh

@@ -156,8 +156,7 @@ parse_server_arguments() {
 
 # Get arguments from the my.cnf file,
 # the only group, which is read from now on is [mysqld]
-if test -x $bindir/my_print_defaults
-then
+if test -x "$bindir/my_print_defaults";  then
   print_defaults="$bindir/my_print_defaults"
 else
   # Try to find basedir in /etc/my.cnf
@@ -175,11 +174,6 @@ else
         print_defaults="$d/bin/my_print_defaults"
         break
       fi
-      if test -x "$d/bin/mysql_print_defaults"
-      then
-        print_defaults="$d/bin/mysql_print_defaults"
-        break
-      fi
     done
   fi
 
@@ -384,7 +378,7 @@ case "$mode" in
       fi
     else
       # Try to find appropriate mysqld process
-      mysqld_pid=`pidof $libexecdir/mysqld`
+      mysqld_pid=`pgrep $libexecdir/mysqld`
 
       # test if multiple pids exist
       pid_count=`echo $mysqld_pid | wc -w`