The relevant files ('libvclplug_gtk3_kde5lo.so',
'lo_kde5filepicker') resulting from the '--enable-gtk3-kde5'
build option are put into the kde-integration package
(e.g. a Debian package when the '--with-package-format=deb'
option is given).

However, so far that package was only created at all when
one of the options '--enable-kde4', '--enable-qt5' or
'--enable-kde5' was given in addition.

Since those are not needed for the gtk3_kde5 vclplug, also
build the kde-integration when none of the others is
built in addition.

Change-Id: I86eb71ac7879c7226c9eaa89774b68125212a75c
Reviewed-on: https://gerrit.libreoffice.org/55310Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>