Fix XML parsing failures due to non-breaking spaces

Using ` ` for non-breaking spaces is not supported in the XML
serialization of HTML5, so replace with the character code equivalent so that
SimpleXML can properly parse the page.

src/DrupalReleaseDate/DrupalIssueCount.php

@@ -258,13 +258,19 @@ public function getXmlDocument(\Guzzle\Http\Message\Response $response) {
             libxml_use_internal_errors(true);
             $document = $response->xml();
         }
-        catch (\RuntimeException $e) {
+        catch (\Guzzle\Common\Exception\RuntimeException $e) {
             libxml_clear_errors();
 
-            // Drupal.org may return invalid XML due to unescaped ampersands
+            // Drupal.org may return invalid XML due to unescaped ampersands and
+            // non-breaking spaces (which aren't valid in XHTML serialization of
+            // HTML5).
             $page = (string) $response->getBody();
 
-            $page = str_replace(' & ', ' & ', $page);
+            $replace = array(
+                ' & '    => ' & ',
+                ' ' => ' ',
+            );
+            $page = str_replace(array_keys($replace), array_values($replace), $page);
 
             $document = new \SimpleXMLElement($page);
         }