MariaDB header error

Question

I had a MySQL server on my Ubuntu dev box (I use a tutorial "how to install a lamp on ubuntu" type of article) and I decided to install mariadb.

So I uninstall mysql and install mariadb.

~$ mysql --version
mysql  Ver 15.1 Distrib 10.0.3-MariaDB, for debian-linux-gnu (i686) using readline 5.1
~$ mysqld --version
mysqld  Ver 10.0.3-MariaDB-1~precise-log for debian-linux-gnu on i686 (mariadb.org binary distribution)

The installation worked fine, all my database worked fine except I get this error when I run the code:

Warning: mysqli::mysqli() [mysqli.mysqli]: Headers and client library minor version mismatch. Headers:50529 Library:100003 in /var/www/test.php on line 5

this is my php code:

  $mysqli = new mysqli("localhost", "root", "", "test");

  if (mysqli_connect_errno()) {
      printf("Connect failed: %s\n", mysqli_connect_error());
      exit();
  }

  $query = "SELECT * FROM test";

  if ($result = $mysqli->query($query)) {

      while ($row = $result->fetch_assoc()) {
          printf ("%s (%s)\n", $row["id"], $row["name"]);
      }
      $result->free();
  }

  $mysqli->close();

and the mysql info:

Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 40
Server version: 10.0.3-MariaDB-1~precise-log mariadb.org binary distribution

Copyright (c) 2000, 2013, Oracle, Monty Program Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]> select version();
+------------------------------+
| version()                    |
+------------------------------+
| 10.0.3-MariaDB-1~precise-log |
+------------------------------+
1 row in set (0.00 sec)

MariaDB [test]> show tables;
+----------------+
| Tables_in_test |
+----------------+
| test           |
+----------------+
1 row in set (0.01 sec)

MariaDB [test]> show create table test\G
*************************** 1. row ***************************
       Table: test
Create Table: CREATE TABLE `test` (
  `id` int(11) DEFAULT NULL,
  `name` varchar(255) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1
1 row in set (0.00 sec)

MariaDB [test]> select * from test;
+------+------+
| id   | name |
+------+------+
|    1 | dev  |
|    2 | qa   |
+------+------+
2 rows in set (0.01 sec)

I tried a mysql_upgrade:

mysql_upgrade --force
Phase 1/3: Fixing table and database names
Phase 2/3: Checking and upgrading tables
Processing databases
information_schema
mysql
mysql.column_stats                                 OK
mysql.columns_priv                                 OK
mysql.db                                           OK
mysql.event                                        OK
mysql.func                                         OK
mysql.gtid_slave_pos                               OK
mysql.help_category                                OK
mysql.help_keyword                                 OK
mysql.help_relation                                OK
mysql.help_topic                                   OK
mysql.host                                         OK
mysql.index_stats                                  OK
mysql.innodb_index_stats                           OK
mysql.innodb_table_stats                           OK
mysql.ndb_binlog_index                             OK
mysql.plugin                                       OK
mysql.proc                                         OK
mysql.procs_priv                                   OK
mysql.proxies_priv                                 OK
mysql.servers                                      OK
mysql.slave_master_info                            OK
mysql.slave_relay_log_info                         OK
mysql.slave_worker_info                            OK
mysql.table_stats                                  OK
mysql.tables_priv                                  OK
mysql.time_zone                                    OK
mysql.time_zone_leap_second                        OK
mysql.time_zone_name                               OK
mysql.time_zone_transition                         OK
mysql.time_zone_transition_type                    OK
mysql.user                                         OK
performance_schema
test
test.test                                          OK
Phase 3/3: Running 'mysql_fix_privilege_tables'...
OK

As far as I know everything there is ok. What's the problem?

Also, is MariaDB ready for production?