Restoring the error handler

Restoring the error handler even if an exception occurs. 
This is something we have to do manually if we catch the Exception somewhere else.
Restoring the error handler

Restoring the error handler no matter what the exception is instead
Update library/Zend/Config/Writer/AbstractWriter.php

Syntax changes
Merge commit 'refs/pull/3441/head' of github.com:zendframework/zf2 into hotfix/restore-error-handler
Forward port #3441