On recent Mac OS versions, the ulimit defaults to 256 by default, but many
systems (eg: some Linux distributions) often limit this value to 1024.
On validation of configuration, Consul now validates that the number of
allowed files descriptors is bigger than http_max_conns_per_client.
This make some unit tests failing on Mac OS.
Use a less important value in unit test, so tests runs well by default
on Mac OS without need for tuning the OS.