update ntttp.c
update ntttp.c

Maybe this is not a bug, just spelling mistake.
e->client_streams is a pointer to pointer of ntttcp_stream_client.
(1)e->client_streams = (struct ntttcp_stream_client **) malloc( sizeof( struct  ntttcp_stream_client *) * total_threads );
alloc an array of ntttcp_stream_client pointer.
(2)e->client_streams[i] = new_ntttcp_client_stream(test);
alloc a ntttcp_stream_client struct.
Microsoft/ntttcp-for-linux,Microsoft/ntttcp-for-linux