gvfs: remove --disable-gconf
gconf support has been dropped since 1.7.0:
https://gitlab.gnome.org/GNOME/gvfs/commit/e22dbb2aeadd3d45a93e702046bc9dc247368f4b
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>