removed invalid processors option
bug #3979 removed invalid processors option (ricoli)

This PR was submitted for the 2.5 branch but it was merged into the 2.3 branch instead (closes #3979).

Discussion
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removed invalid processors option

As per https://github.com/symfony/MonologBundle/issues/77

Commits
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a462258 removed invalid processors option
Merge branch '2.3' into 2.4