BackgroundParser: Fix crash-on-exit
Currently running JobInterfaces where double-deleted, once through
~BackgroundParserPrivate, once through ref counting logic when deleting
ThreadWeaver::Weaver.
Just let the Weaver take care of deleting. Every job in m_parseJobs is
also in m_weaver.
BUG: 359442
FIXED-IN: 5.0.0