better handle PDOExceptions during open transaction in feed update

classes/rssutils.php

@@ -192,6 +192,13 @@ class RSSUtils {
 					RSSUtils::update_rss_feed($tline["id"], true, false);
 				} catch (PDOException $e) {
 					Logger::get()->log_error(E_USER_NOTICE, $e->getMessage(), $e->getFile(), $e->getLine(), $e->getTraceAsString());
+
+					try {
+						$pdo->rollback();
+					} catch (PDOException $e) {
+						// it doesn't matter if there wasn't actually anything to rollback, PDO Exception can be
+						// thrown outside of an active transaction during feed update
+					}
 				}
 				_debug_suppress(false);