Txn contx conflict, fix

there is only 1 real change,  in this RP which could have any real effect,  but it seems it changes the results of running this test.

with this RP we get 

txnConflict: TxnCounter{committed=17326, rolled=0, failedRoles=0} from 1000 worker threads
txnConflict: TxnCounter{committed=17410, rolled=0, failedRoles=0} from 1000 worker threads
txnConflict: TxnCounter{committed=17519, rolled=0, failedRoles=0} from 1000 worker threads
txnConflict: TxnCounter{committed=17593, rolled=0, failedRoles=0} from 1000 worker threads

and we no longer see the test doing 

INFO  18:41:06 txnConflict Waiting for stop completion: 00d 00h 07m 55s
INFO  18:43:05 txnConflict Waiting for localVerify completion: 00d 00h 01m 49s


previously we would see 
txnConflict: TxnCounter{committed=0, rolled=1525, failedRoles=0} from 1000 worker threads
txnConflict: TxnCounter{committed=3, rolled=1383, failedRoles=0} from 1000 worker threads 
random is used now, to init the key and inc,  
I know the -1 +1 is also a problem