fixed a bug in the regex pattern to converts tabs and spaces into a single space

http://codeigniter.com/bug_tracker/bug/6662/
diff --git a/system/database/DB_driver.php b/system/database/DB_driver.php
index dac4c8b..42b6a75 100644
--- a/system/database/DB_driver.php
+++ b/system/database/DB_driver.php
@@ -1213,7 +1213,7 @@
 		}
 
 		// Convert tabs or multiple spaces into single spaces
-		$item = preg_replace('/[\t| ]+/', ' ', $item);
+		$item = preg_replace('/[\t ]+/', ' ', $item);
 	
 		// If the item has an alias declaration we remove it and set it aside.
 		// Basically we remove everything to the right of the first space