`checkPeers` should be supplied to `nwo.InstantiateChaincode`
if called separately, so that checks are performed to ensure
the instantiation. Otherwise, an immediate query/invoke following
this would fail, because that deploy tx may not be committed yet.

Change-Id: I8e870b183c279aca53961745031fdee7085efe18
Signed-off-by: Jay Guo <guojiannan1101@gmail.com>