Don't trim whitespace from sections of the response in IXR_Client. Fixes #12559 props apeatling.

git-svn-id: https://develop.svn.wordpress.org/trunk@14677 602fd350-edb4-49c9-b593-d223f7449a82

wp-includes/class-IXR.php

@@ -581,7 +581,8 @@ class IXR_Client {
                 $gettingHeaders = false;
             }
             if (!$gettingHeaders) {
-                $contents .= trim($line);
+            	// WP#12559 remove trim so as to not strip newlines from received response.
+                $contents .= $line;
             }
             if ($this->debug) {
                 $debug_contents .= $line;