kbuildsycoca's globs2 file parser to add rather than replace, by default, as
discussed on xdg-list.
This allows users to delete all patterns from a mimetype in keditfiletype.
BUG: 184181

Note: this will only really work after the next shared-mime-info release.
With shared-mime-info <= 0.60, deleteall has no effect so globs are always appended.

svn path=/trunk/KDE/kdebase/runtime/; revision=951933