Remove all old passwordless root account lines when using unix auth

This closes a potential security vulnerability. In bug report at
https://bugs.launchpad.net/ubuntu/+source/mariadb-10.0/+bug/1561062
it was pointed out, that is name resolve is skipped and TCP is
forced, localhost users can being detected as connecting via host
localhost and the passwordless root lines would apply and let
user inside. This is not intended and potentially dangerous,
so remove the lines. They are most likely useless and legacy
anyway.

debian/changelog

@@ -5,6 +5,8 @@ mariadb-10.0 (10.0.24-6) UNRELEASED; urgency=low
   * Add breaks/replaces for mariadb-client to accommodate the above.
   * Add conflicts/breaks/replaces for MySQL 5.7 series packages now
     when mysql-5.7 entered the Ubuntu repositories (LP: #1568285).
+  * Remove all old passwordless root account lines to close a potential
+    security vulnerability (LP: #1561062).
 
  -- Otto Kekäläinen <otto@debian.org>  Sat, 09 Apr 2016 14:47:22 +0300
 

debian/patches/mdev-8375-passwordless-root-via-socket-auth.patch

@@ -10,12 +10,14 @@ Bug: https://jira.mariadb.org/browse/MDEV-8375
 
 --- a/scripts/mysql_system_tables_data.sql
 +++ b/scripts/mysql_system_tables_data.sql
-@@ -29,7 +29,7 @@ SELECT LOWER( REPLACE((SELECT REPLACE(@@
+@@ -29,10 +29,7 @@
  -- Fill "user" table with default users allowing root access
  -- from local machine if "user" table didn't exist before
  CREATE TEMPORARY TABLE tmp_user LIKE user;
 -INSERT INTO tmp_user VALUES ('localhost','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0,'','','N', 'N');
+-REPLACE INTO tmp_user SELECT @current_hostname,'root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0,'','','N','N' FROM dual WHERE @current_hostname != 'localhost';
+-REPLACE INTO tmp_user VALUES ('127.0.0.1','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0,'','','N','N');
+-REPLACE INTO tmp_user VALUES ('::1','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0,'','','N','N');
 +INSERT INTO tmp_user VALUES ('localhost','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0,'unix_socket','','N', 'N');
- REPLACE INTO tmp_user SELECT @current_hostname,'root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0,'','','N','N' FROM dual WHERE @current_hostname != 'localhost';
- REPLACE INTO tmp_user VALUES ('127.0.0.1','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0,'','','N','N');
- REPLACE INTO tmp_user VALUES ('::1','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','',0,0,0,0,'','','N','N');
+ INSERT INTO user SELECT * FROM tmp_user WHERE @had_user_table=0;
+ DROP TABLE tmp_user;