Upgrade python/google-api-python-client to v1.7.9

Test: None
Exempt-From-Owner-Approval: Upgrade library
Change-Id: I958ce78411ada69091c58ee7780feb766d7bd1a2
diff --git a/METADATA b/METADATA
index 616b802..3548628 100644
--- a/METADATA
+++ b/METADATA
@@ -9,10 +9,10 @@
     type: GIT
     value: "https://github.com/google/google-api-python-client"
   }
-  version: "v1.7.8"
+  version: "v1.7.9"
   last_upgrade_date {
     year: 2019
-    month: 2
-    day: 1
+    month: 5
+    day: 22
   }
 }