do not read twice (#152)

diff --git a/server/resource/v1/common.go b/server/resource/v1/common.go
index 06f52be..51ae38a 100644
--- a/server/resource/v1/common.go
+++ b/server/resource/v1/common.go
@@ -57,7 +57,7 @@
 func ReadClaims(ctx context.Context) map[string]interface{} {
 	i := rbacframe.FromContext(ctx)
 	if i != nil {
-		return rbacframe.FromContext(ctx).(map[string]interface{})
+		return i.(map[string]interface{})
 	}
 	return nil
 }