bugfix: change_user should only take the password

of the previous user if it takes the username too.
otherwise it can never change to a passwordless account

client/mysqltest.cc

@@ -36,6 +36,7 @@
 #include "client_priv.h"
 #include <mysql_version.h>
 #include <mysqld_error.h>
+#include <sql_common.h>
 #include <m_ctype.h>
 #include <my_dir.h>
 #include <hash.h>
@@ -3610,6 +3611,7 @@ void do_change_user(struct st_command *command)
   }
 
   if (!ds_user.length)
+  {
     dynstr_set(&ds_user, mysql->user);
 
     if (!ds_passwd.length)
@@ -3617,6 +3619,7 @@ void do_change_user(struct st_command *command)
 
     if (!ds_db.length)
       dynstr_set(&ds_db, mysql->db);
+  }
 
   DBUG_PRINT("info",("connection: '%s' user: '%s' password: '%s' database: '%s'",
                       cur_con->name, ds_user.str, ds_passwd.str, ds_db.str));