not possible to use zero operation count

[symat]

Previously, if you defined maxexecutiontime and not defined operationcount parameter (or set operationcount=0), then you were able to run YCSB for a given period of time and measure the number of operations you get during the load test.

Since #1323 was merged, it it not possible to use operationcount=0, as the thread count will be set to 0 in this case and no client thread will be created:

YCSB/core/src/main/java/site/ycsb/Client.java

Lines 421 to 424 in 4b19340

	if (threadcount > opcount){
	threadcount = opcount;
	System.out.println("Warning: the threadcount is bigger than recordcount, the threadcount will be recordcount!");
	}

The solution would be to change the is statement to: if (threadcount > opcount && opcount > 0)

What do you think?
(should I create a PR?)

[busbey]

Yes please, that solution sounds great.