Calling CacheHasBeenInvalidated instead of RefreshCache

At this point we know these values have already been marked as invalid.
There is no reason to call RefreshCache on them and go through that
pipeline again. Furthermore that pipeline is currently waiting for valid
data, so it will not fire off the invalidation events a second time.

Author: StanleyGoldman

src/GitHub.Api/Git/Repository.cs

@@ -92,7 +92,7 @@ public void Start()
         {
             foreach (var cacheType in cacheInvalidationRequests)
             {
-                RefreshCache(cacheType);
+                CacheHasBeenInvalidated(cacheType);
             }
         }