Delete duplicate check in _checkProposalRequest
Delete duplicate check in _checkProposalRequest

There are duplicate check in _checkProposalRequest(),
the second one was deleted.

Change-Id: I2b3a3fbdddb5c3ecbdf7738480f65feee909a0b6
Signed-off-by: Nao Nishijima <739e1b294c8b6757c98b7b399be63e41686762e7@hal.hitachi.com>

ratnakar-asara/fabric-sdk-node,adityachap/fabric-sdk-node,ratnakar-asara/fabric-sdk-node,adityachap/fabric-sdk-node,ratnakar-asara/fabric-sdk-node,ratnakar-asara/fabric-sdk-node