minor symfony#25453 [Console] Fix console tests by adding the missing condition (Simperfit)

This PR was merged into the 3.3 branch.

Discussion
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[Console] Fix console tests by adding the missing condition

| Q             | A
| ------------- | ---
| Branch?       | 3.3
| Bug fix?      | yes
| New feature?  | no <!-- don't forget to update src/**/CHANGELOG.md files -->
| BC breaks?    | no
| Deprecations? | no <!-- don't forget to update UPGRADE-*.md files -->
| Tests pass?   | yes
| Fixed tickets | none
| License       | MIT
| Doc PR        |

The old conditions was testing that the exit code is different than 0. I just add this tests back since it is needed.
![resized_20171211_192030_2217](https://user-images.githubusercontent.com/3451634/33872253-5db07958-df16-11e7-85e9-4fc0cb5002ce.jpeg)

Commits
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57f8129 [Console] Fix console tests by adding the missing condition

Author: chalasr

src/Symfony/Component/Console/Event/ConsoleErrorEvent.php

@@ -78,6 +78,6 @@ public function setExitCode($exitCode)
      */
     public function getExitCode()
     {
-        return null !== $this->exitCode ? $this->exitCode : (is_int($this->error->getCode()) ? $this->error->getCode() : 1);
+        return null !== $this->exitCode ? $this->exitCode : (is_int($this->error->getCode()) && 0 !== $this->error->getCode() ? $this->error->getCode() : 1);
     }
 }