bug #20991 [cache] Bump RedisAdapter default timeout to 5s (Nicofuma)

This PR was merged into the 3.1 branch.

Discussion
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[cache] Bump RedisAdapter default timeout to 5s

| Q             | A
| ------------- | ---
| Branch?       | 3.2
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

Bump RedisAdapter timeout to 5s because (at least with Predis) 0 means 0s

Commits
-------

eaca2a4 [cache] Bump RedisAdapter timeout to 5s

src/Symfony/Component/Cache/Adapter/RedisAdapter.php

@@ -25,8 +25,8 @@ class RedisAdapter extends AbstractAdapter
     private static $defaultConnectionOptions = array(
         'class' => null,
         'persistent' => 0,
-        'timeout' => 0,
-        'read_timeout' => 0,
+        'timeout' => 30,
+        'read_timeout' => 30,
         'retry_interval' => 0,
     );
     private $redis;