* gnu/packages/nicotine.scm (nicotine+): Update to 2.1.2.
[inputs]: Remove python-mutagen and python-dbus. Add python-pytaglib.
[native-inputs]: Add gettext-minimal.
[arguments]: Apply the 'glib-or-gtk-wrap' and 'glib-or-gtk-compile-schemas'
phases from the glib-or-gtk-build-system.
Signed-off-by: Leo Famulari <leo@famulari.name>