removed defaultValue for replication option to allow cluster option

[ivoba]

Predis now has built-in support for redis-cluster:
https://github.com/nrk/predis/blob/v1.1/README.md#cluster

However this options has only effect when the replication option is omitted.
But due to the defaultFalse configuration, the option['replication'] was always present and prevented Predis to enter cluster mode:
https://github.com/nrk/predis/blob/v1.1/src/Client.php#L123

An example config is:

snc_redis:
    clients:
      default:
          type: predis
          alias: default
          dsn:
              - 'redis://%cache.redis_host.one%:%cache.redis_port%/%cache.redis_db%'
              - 'redis://%cache.redis_host.two%:%cache.redis_port%/%cache.redis_db%'
          options:
            profile: 3.2
            cluster: "redis"

With "redis-custer" or "redis" as cluster option commands like this will automatically be resolved:
MOVED 14966 cache.redis_host.two:6381

This probably needs some more work as replication now can be even more than boolean:
https://github.com/nrk/predis/blob/v1.1/README.md#replication

[snc]

Does your setup work with #307?

[ivoba]

@snc #307 will not work for cluster: "redis" because the options array will still have the key "replication" with null and so the isset function will not let the option pass.
When ->defaultNull() would be removed it would probably work.

However as i mentioned in #306 i would prefer not to predefine/limit the options by the bundle configuration at all.

[jontorrado]

What about merging this PR @snc? This fixes redis cluster for newer predis versions.

[ebarault]

@ivoba @snc is there any progress on this?

Is there currently a working config with predis 1.1.1 that allows cluster: redis option to work ?

I'm using AWS Elasticache Redis with configuration endpoint and can't find a way to solve MOVED 14966 ... exceptions

[curry684]

I'm closing this PR as the line of code it's changing has already been modified since, and no longer has a default anyway in that new implementation so it's no longer relevant.