Release google-api-python-client 1.7.4 (#540)

Release v1.7.4
diff --git a/CHANGELOG b/CHANGELOG
index eb4afea..30e8c7e 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,10 @@
+v1.7.4
+  Version 1.7.4
+ 
+  Bugfix release
+
+  - Catch ServerNotFoundError to retry the request (#532)
+
 v1.7.3
   Version 1.7.3