[5.6] add *scan methods to work on phpredis connection v2

[ragingdave]

This adds the adapter methods to properly utilize PhpRedis commands for scan, sscan, hscan, and zscan. fixes #24222 .... take 2.

I reorganized the methods, fixed docblocks and tried to make the changes to the tests a bit clearer. The reason for the core InteractsWithRedis changes is because setUp runs after any dataProviders so rather than having to call connect on every driver, having the configureConnections call in both the setUp and the dataProvider means that everything works. Additionally the prefix addition ensures that all commands are tested with both a prefix and non-prefixed connection as there is currently a bug awaiting this merge to be fixed as well (#24257).

[taylorotwell]

Merged.

[taylorotwell]

And... it broke Travis.

https://travis-ci.org/laravel/framework/builds/383206574?utm_source=email&utm_medium=notification

I'm just reverting all this again.

[taylorotwell]

Reverted. Feel free to PR again if it won't break tests.

[ragingdave]

Well silly Travis....I'll take another pass to try and figure out what went wrong...Nothing happened on my test run and the initial Travis Run for the commit itself...I'll check for any new commits to see if there are any conflicts.

[ragingdave]

@taylorotwell Looks like the changes added in the merge changed the logic. The $counter is a pass by reference variable, which only changes after the call to the client. I will refactor to include most of the style changes you made, but the scan methods will all end up looking like the sscan version with the $client call happening and then returning the array. Additionally due to this odd nature, would you prefer a comment on those methods stating something about the pass by reference behavior?

[tillkruss]

@ragingdave: Yeah, add a comment, it's easy to remove or refactor.

[saurovh]

How should this change be used in laravel 5.4 ?