[FAB-10240] Remove duplicated checking on TxID
[FAB-10240] Remove duplicated checking on TxID

When doing endorsement, the TxID is checked in
core/common/validation/msgvalidation.go to make sure it equals to
SHA256(nonce+creator).

After that, check whether it is empty again in the core/endorser/endorser.go.
However, the later checking actually won't happen because of the previous validation.

This patchset removed the unused empty checking code.

Change-Id: I99de8e833432200196741b55555d9006f8cb86a0
Signed-off-by: Baohua Yang <3c1728ff36d27dfd99f7c17cb4c2fbaf35fbcddf@gmail.com>

muralisrini/fabric,xixuejia/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric,xixuejia/fabric,stemlending/fabric,manish-sethi/fabric-sidedb,jimthematrix/fabric,manish-sethi/fabric-sidedb,hyperledger/fabric,manish-sethi/fabric-sidedb,binhn/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,binhn/fabric,hyperledger/fabric,muralisrini/fabric,jimthematrix/fabric,manish-sethi/fabric-sidedb,muralisrini/fabric,manish-sethi/fabric,binhn/fabric,stemlending/fabric,stemlending/fabric,stemlending/fabric,xixuejia/fabric