Merge pull request bitcoin#375 from voisine/patch-4

fix BIP141 nested P2SH scriptSig byte representation

Author: luke-jr

bip-0141.mediawiki

@@ -166,7 +166,7 @@ The following example is the same 1-of-2 multi-signature P2WSH witness program,
 
     witness:      0 <signature1> <1 <pubkey1> <pubkey2> 2 CHECKMULTISIG>
     scriptSig:    <0 <32-byte-hash>>
-                  (0x0020{32-byte-hash})
+                  (0x220020{32-byte-hash})
     scriptPubKey: HASH160 <20-byte-hash> EQUAL
                   (0xA914{20-byte-hash}87)