providers/dnsimple|heroku: handle ComputedAttrsUpdate

Author: pearkes

builtin/providers/dnsimple/resource_dnsimple_record.go

@@ -142,6 +142,9 @@ func resource_dnsimple_record_diff(
 			"priority",
 			"domain_id",
 			"ttl",
+		},
+
+		ComputedAttrsUpdate: []string{
 			"hostname",
 		},
 	}

builtin/providers/heroku/resource_heroku_app.go

@@ -203,6 +203,10 @@ func resource_heroku_app_diff(
 			"id",
 			"config_vars",
 		},
+
+		ComputedAttrsUpdate: []string{
+			"heroku_hostname",
+		},
 	}
 
 	return b.Diff(s, c)