Revert "Abstracting the loading of files in the config directory depending on environments."

This reverts commit 5c1aa631c5f5ec2f6b75ba1158178418e50ba11a.
diff --git a/system/libraries/Upload.php b/system/libraries/Upload.php
index 5108afa..826bcce 100644
--- a/system/libraries/Upload.php
+++ b/system/libraries/Upload.php
@@ -952,12 +952,17 @@
 	{
 		global $mimes;
 
-		if (count($this->mimes) === 0)
+		if (count($this->mimes) == 0)
 		{
-			load_environ_config('mimes');
-
-			// Return FALSE if we still have no mimes after trying to load them up.
-			if (count($this->mimes) === 0)
+			if (defined('ENVIRONMENT') AND is_file(APPPATH.'config/'.ENVIRONMENT.'/mimes.php'))
+			{
+				include(APPPATH.'config/'.ENVIRONMENT.'/mimes.php');
+			}
+			elseif (is_file(APPPATH.'config/mimes.php'))
+			{
+				include(APPPATH.'config//mimes.php');
+			}
+			else
 			{
 				return FALSE;
 			}