grpc client/server fixes (#1355)

* grpc client/server fixes

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

error.go

@@ -17,18 +17,21 @@ func microError(err error) error {
 	}
 
 	// grpc error
-	if s, ok := status.FromError(err); ok {
-		details := s.Details()
-		if len(details) == 0 {
-			if e := errors.Parse(s.Message()); e.Code > 0 {
-				return e // actually a micro error
-			}
-			return errors.InternalServerError("go.micro.client", s.Message())
-		}
-		// return first error from details
-		return details[0].(error)
+	s, ok := status.FromError(err)
+	if !ok {
+		return err
 	}
 
-	// do nothing
-	return err
+	// return first error from details
+	if details := s.Details(); len(details) > 0 {
+		return microError(details[0].(error))
+	}
+
+	// try to decode micro *errors.Error
+	if e := errors.Parse(s.Message()); e.Code > 0 {
+		return e // actually a micro error
+	}
+
+	// fallback
+	return errors.InternalServerError("go.micro.client", s.Message())
 }