[FAB-13428] Make TestReplicateChainsFailures robust
[FAB-13428] Make TestReplicateChainsFailures robust

There was a redundant sending of a block, which got the client
and the mock server out of sync occasionally.

Ran the test 2,000 times and it didn't fail afterwards.

Change-Id: I09631632a16d3ee42fc51fbb809f3027e50a0973
Signed-off-by: yacovm <632344b5da9bd743456189af4db4b56472defb8c@il.ibm.com>

xixuejia/fabric,xixuejia/fabric,xixuejia/fabric