Fix a PHP 8.1 deprecated use of preg_match with a NULL argument master
Summary: These calls are preventing users to browse subversion/mercurial repositories in PHP 8.1+. Indeed, a similar bug affecting git repositories was already addressed in another commit (rP6b8ec50148909938850b5acfd11725ae23a8e31b). This commit harmonize both DiffusionSvnRequest and DiffusionMercurialRequest with DiffusionGitRequest Fix T15607 Test Plan: - Sign in - Open a diffusion SVN/Mercurial repository - You should not get a RuntimeException concerning this preg_match call Reviewers: O1 Blessed Committers, Sten, valerio.bozzolan Reviewed By: O1 Blessed Committers, Sten, valerio.bozzolan Subscribers: Sten, tobiaswiese, valerio.bozzolan, Matthew, Cigaryno Maniphest Tasks: T15607 Differential Revision: https://we.phorge.it/D25397