[CO] Bugfix ReplaceProcessor.php to PHP 7.1 and 7.2

[Nobodaddy]

Just another bugfix for PHP 7.1 and 7.2

Questions	Answers
Branch?	1.6.1.x
Description?	Bugfix for PHP 7.1 and 7.2 to make the SQL Manager work again. Must be applied together with #12643
Type?	bug fix
Category?	CO
BC breaks?	no
Deprecations?	no
Fixed ticket?	(optional) If this PR fixes an Issue, please write "Fixes #[issue number]" here.
How to test?	Please indicate how to best verify that this PR is correct.

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This change is 

[mickaelandrieu]

Hello @Nobodaddy,

how can we validate this pull request, please?

Thanks

[PierreRambaud]

First of all, thank you for contributing to the PrestaShop project!

As you may already know, normal maintenance support for PrestaShop 1.6 ended in October 2018, which is now in extended maintenance mode until June 30, 2019.

During this period, and in order to ensure the stability of current 1.6 shops, only critical bugs and and security fixes will be accepted in the 1.6.1.x branch. If your contribution applies also to the 1.7 branch, please rebase it into the develop branch so that we may include it into the next 1.7 release.

Thanks for your understanding!