Enable auto-generating sources rules

pkg/cloudprovider/providers/openstack/BUILD

@@ -75,3 +75,16 @@ go_test(
         "//vendor:github.com/rackspace/gophercloud/openstack/compute/v2/servers",
     ],
 )
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [":package-srcs"],
+    tags = ["automanaged"],
+)