Old Indian defense variation: 1. d4 d6 2. c4 Nf6 3. Nc3 Nc6 : how should White respond? I had the following game which transposed to an Old Indian defense position:

1. d4 d6 2. c4 Nf6 3. Nc3

But then Black did not follow with the main line: 3 ... e5 (see wikipedia article) but rather with: 3... Nc6. 

[FEN ""]
1. d4 d6 2. c4 Nf6 3. Nc3 Nc6 (3... e5)


I couldn't find this variation discussed anywhere which leads me to think it is likely an inferior line for Black. If so, how should White continue to gain advantage? 4. e4 perhaps ?
The best reply for white and most usual in that position is Nf3, just finishing development and trying to castle kingside.

A normal continuation could be :

 [FEN ""]
  1. d4 d6 2. c4 Nf6 3. Nc3 Nc6 4. Nf3 e5 5. e3 Bg4 6. Be2 Be7 7. O-O O-O *


Black should play e5 sooner or later or he will not gain control of the center and space for his pieces