Ignore file size limit for internal data files.

Summary:
I have an update pending for kdev-php's internal data file,
which would bring it above the 5MB size limit. This code
adds an exception for files inside kdev* related data dirs,
so that the limit doesn't apply for those.

Reviewers: brauch

Reviewed By: brauch

Subscribers: brauch, kdevelop-devel

Tags: KDevelop

Differential Revision: https://phabricator.kde.org/D14789