Fix Truncate Error Issue when using views in a Unittest.

When using a view in a SilverStripe project, whenever the tear down scripts for the Unittests are run the following error occurs:

Couldn't run query:
TRUNCATE "ActivityPoints_view"
Table 'ss_tmpdb2391727.ActivityPoints_view' doesn't exist

This was due to the MySQLSchemaManager::tableList() function assuming that all records in the TABLES were actual tables containing data.

This small tweak fixes the issue by modifying the SQL to filter out views from the list before truncating.

model/connect/MySQLSchemaManager.php

@@ -336,7 +336,7 @@ public function indexList($table) {
 
 	public function tableList() {
 		$tables = array();
-		foreach ($this->query("SHOW TABLES") as $record) {
+		foreach ($this->query("SHOW FULL TABLES WHERE Table_Type != 'VIEW'") as $record) {
 			$table = reset($record);
 			$tables[strtolower($table)] = $table;
 		}