Fix length reflection in SQLServer

Don't reflect TEXT column lengths in SQLServer. Because SQLServer text
columns hold ~2GB of data there is no meaningful length to them.

Refs #5506

lib/Cake/Test/Case/Model/Datasource/Database/SqlserverTest.php

@@ -449,6 +449,15 @@ class SqlserverTest extends CakeTestCase {
 				'Null' => 'YES',
 				'Size' => '0',
 			),
+			(object)array(
+				'Default' => null,
+				'Field' => 'description',
+				'Key' => '0',
+				'Type' => 'text',
+				'Length' => 16,
+				'Null' => 'YES',
+				'Size' => '0',
+			),
 		));
 		$this->db->executeResultsStack = array($SqlserverTableDescription);
 		$dummyModel = $this->model;
@@ -485,6 +494,12 @@ class SqlserverTest extends CakeTestCase {
 				'default' => null,
 				'length' => 8,
 			),
+			'description' => array(
+				'type' => 'text',
+				'null' => true,
+				'default' => null,
+				'length' => null,
+			)
 		);
 		$this->assertEquals($expected, $result);
 		$this->assertSame($expected['parent_id'], $result['parent_id']);