Fix memory leaks (found by ASAN)

Summary:
They don't matter much in practice, except that they make an
ASAN-enabled build abort when protocolgen is running.

Test Plan: make protocolgen && make -j1, in an ASAN build => protocolgen no longer aborts the build

Reviewers: dvratil

Reviewed By: dvratil

Subscribers: kde-pim

Tags: KDE PIM

Differential Revision: https://phabricator.kde.org/D21068