Fix variable name to allow text retrieval

From the "I don't understand how this ever worked" files.

cron/full_text.php

@@ -50,7 +50,7 @@
 	curl_setopt($ch, CURLOPT_HEADER, 0);
 	curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
 	curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
-	$full_text = curl_exec($ch);
+	$response = curl_exec($ch);
 
 	/*
 	 * Check that the cURL request was successful (HTTP status code 2XX).