Adding doc.go files for packages
diff --git a/openstack/identity/v2/tokens/doc.go b/openstack/identity/v2/tokens/doc.go
index d26f642..31cacc5 100644
--- a/openstack/identity/v2/tokens/doc.go
+++ b/openstack/identity/v2/tokens/doc.go
@@ -1,6 +1,5 @@
-/*
-Package tokens contains functions that issue and manipulate identity tokens.
-
-Reference: http://developer.openstack.org/api-ref-identity-v2.html#identity-auth-v2
-*/
+// Package tokens provides information and interaction with the token API
+// resource for the OpenStack Identity service.
+// For more information, see:
+// http://developer.openstack.org/api-ref-identity-v2.html#identity-auth-v2
package tokens