remove dead code in yaml component
merged branch gimler/cleamup_yaml (PR #7264)

This PR was submitted for the master branch but it was merged into the 2.1 branch instead (closes #7264).

Commits
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edda254 remove dead code in yaml component

Discussion
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remove dead code in yaml component

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| License       | MIT

Cleanup unused code.

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by fabpot at 2013-03-06T16:27:57Z

Can you explain why it is not needed anymore?

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by igorw at 2013-03-06T16:44:30Z

`$subject` is no longer used anywhere. The `substr` is now done inline in the `preg_match` call. This code is effectively dead.