don't smoke test UID when testing user resource

[jazaval]

This PR stops checking for the specific sequential uid after creating test cookbook users. We're not actually specifying a desired uid in the resource call, so this test is creating some false failures.

[americanhanko]

Build failure caused by system_preference[disable computer sleep] resource being updated during second chef-client run when enforce_idempotence is true

2018-10-19T02:01:46.1415890Z        Recipe: macos::keep_awake
2018-10-19T02:01:46.1861110Z          * system_preference[disable computer sleep] action set
2018-10-19T02:01:46.1863180Z            - set computersleep to Never
2018-10-19T02:01:46.1864090Z            - update disable computer sleep
2018-10-19T02:01:46.1866080Z            -   set setting to "Never" (was "10")
2018-10-19T02:01:46.2337060Z            * execute[/usr/sbin/systemsetup, -setcomputersleep, Never] action run
2018-10-19T02:01:46.2337870Z              - execute ["/usr/sbin/systemsetup", "-setcomputersleep", "Never"]
2018-10-19T02:01:47.2341440Z            * ruby_block[sleep one second] action run
2018-10-19T02:01:47.2342620Z              - execute the ruby block sleep one second
2018-10-19T02:01:47.2345040Z          
2018-10-19T02:01:47.2792670Z          * system_preference[disable display sleep] action set (up to date)
2018-10-19T02:01:47.3212100Z          * system_preference[disable hard disk sleep] action set (up to date)
2018-10-19T02:01:47.3639180Z          * system_preference[restart if the computer becomes unresponsive] action set (up to date)
2018-10-19T02:01:47.3644110Z          * system_preference[wake the computer when accessed using a network connection] action set (skipped due to not_if)
2018-10-19T02:01:47.3649900Z          * system_preference[restart after a power failure] action set (skipped due to not_if)
2018-10-19T02:01:47.3656240Z          * system_preference[pressing power button does not sleep computer] action set (skipped due to only_if)
2018-10-19T02:01:47.3925690Z          * system_preference[allow remote apple events] action set (up to date)
2018-10-19T02:01:47.4184990Z          * system_preference[set the network time server] action set (up to date)
2018-10-19T02:01:47.4469490Z          * system_preference[set the time zone] action set (up to date)
2018-10-19T02:01:47.4838250Z          * system_preference[enable remote login] action set (up to date)
2018-10-19T02:01:47.5355250Z          * defaults[com.apple.screensaver] action run (skipped due to not_if)
2018-10-19T02:01:47.6085240Z        
2018-10-19T02:01:47.6085690Z        Running handlers:
2018-10-19T02:01:47.6085920Z        First chef run should have reached a converged state.
2018-10-19T02:01:47.6087080Z        Resources updated in a second chef-client run:
2018-10-19T02:01:47.6088950Z        - system_preference[disable computer sleep]
2018-10-19T02:01:47.6158850Z        [2018-10-18T19:00:37-07:00] FATAL: Chef::Exceptions::ChildConvergeError: Chef run process terminated by signal 9 (KILL)
2018-10-19T02:01:47.6160820Z        [2018-10-18T19:00:37-07:00] FATAL: Chef::Exceptions::ChildConvergeError: Chef run process terminated by signal 9 (KILL)

[mjmerin]

Don't forget to update the changelog.