modemmanager: add dbus-glib dependency

* otherwise fails with:
  | checking for MM... no
  | configure: error: Package requirements (dbus-glib-1 >= 0.86 glib-2.0
    >= 2.18 gmodule-2.0 gobject-2.0) were not met:
  |
  | No package 'dbus-glib-1' found

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>