access sqlite3 db through sqlite3 instead of PDO

PDOStatement::rowCount() is source of problems (used by num_rows() in ci3)
See: https://stackoverflow.com/questions/883365/row-count-with-pdo

As a consequence, switch to PHP's sqlite3 driver

application/config/database.php

@@ -142,12 +142,12 @@
 );
 
 $db['kalkun_sqlite3'] = array(
-	'dsn'	=> 'sqlite:/path/to/kalkun.sqlite',
-	'hostname' => 'localhost',
+	'dsn'	=> '',
+	'hostname' => '',
 	'username' => '',
 	'password' => '',
-	'database' => '',
-	'dbdriver' => 'pdo',
+	'database' => '/path/to/kalkun.sqlite',
+	'dbdriver' => 'sqlite3',
 	'dbprefix' => '',
 	'pconnect' => FALSE,
 	'db_debug' => (ENVIRONMENT !== 'production'),

application/helpers/kalkun_helper.php

@@ -225,7 +225,7 @@ function is_ajax()
 function get_database_property($driver)
 {
 	// valid and supported driver
-	$valid_driver = array('postgre', 'mysql', 'mysqli', 'pdo');
+	$valid_driver = array('postgre', 'mysql', 'mysqli', 'sqlite3');
 
 	if ( ! in_array($driver, $valid_driver))
 	{
@@ -250,12 +250,11 @@ function get_database_property($driver)
 	$mysqli['escape_char'] = '`';
 	$mysqli['driver'] = 'mysqli';
 
-	$pdo['name'] = 'sqlite';
-	$pdo['file'] = 'sqlite';
-	$pdo['human'] = 'SQLite3 (Using PDO)';
-	$pdo['escape_char'] = '';
-	$pdo['driver'] = 'pdo_sqlite';
-
+	$sqlite3['name'] = 'sqlite';
+	$sqlite3['file'] = 'sqlite';
+	$sqlite3['human'] = 'SQLite3';
+	$sqlite3['escape_char'] = '';
+	$sqlite3['driver'] = 'sqlite3';
 	return ${$driver};
 }