! fix #1882 case normalization should only affect key

sources/CurlFetchWebdata.class.php

@@ -286,7 +286,6 @@ private function _buildPostData($post_data)
 		}
 		else
 			return $post_data;
-
 	}
 
 	/**
@@ -352,7 +351,7 @@ private function _headerCallback($cr, $header)
 
 		// set proper headers only
 		if (isset($temp[0]) && isset($temp[1]))
-			$this->_headers[strtolower($temp[0])] = strtolower(trim($temp[1]));
+			$this->_headers[strtolower($temp[0])] = trim($temp[1]);
 
 		// return the length of what was *passed* unless you want a Failed writing header error ;)
 		return strlen($header);