fix: use output hashMd5 for control files
Summary:
Control files are a relatively new concept and only used by the retention value
for now. Identify this data by the improved hash function, which also hashes
the name in case no EDID information is provided.
FIXED-IN: 5.17.3
Test Plan: Reads in and writes retention data.
Reviewers: Plasma, davidedmundson
Reviewed By: Plasma, davidedmundson
Subscribers: plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D25021