gnu: Use HTTPS for supported freedesktop.org home pages.

gnu: Use HTTPS for supported freedesktop.org home pages.

* gnu/packages/fontutils.scm (fontconfig)[home-page]: Use HTTPS.
* gnu/packages/freedesktop.scm (python-pyxdg, accountsservice)
(modem-manager, telepathy-mission-control, telepathy-mission-control)
(colord-gtk, desktop-file-utils)[home-page]: Likewise.
* gnu/packages/ghostscript.scm (libspectre)[home-page]: Likewise.
* gnu/packages/glib.scm (dbus, dbus-glib, telepathy-glib)[home-page]:
Likewise.
* gnu/packages/gnome.scm (shared-mime-info, hicolor-icon-theme)
(libxklavier, colord, upower)[home-page]: Likewise.
* gnu/packages/gstreamer.scm (orc, python-gst)[home-page]: Likewise.
* gnu/packages/libcanberra.scm (sound-theme-freedesktop)[home-page]:
Likewise.
* gnu/packages/libreoffice.scm (libexttextcat)[home-page]: Likewise.
* gnu/packages/polkit.scm (polkit-gnome, polkit-gnome)[home-page]:
Likewise.
* gnu/packages/pulseaudio.scm (pavucontrol)[home-page]: Likewise.
* gnu/packages/python.scm (python-dbus)[home-page]: Likewise.
* gnu/packages/xdisorg.scm (startup-notification)[home-page]: Likewise.