guitartune: add dependency on dbus, dbus-glib

* | configure:13083: error: Package requirements (gtk+-2.0 >= 2.8
    libglade-2.0 >= 2.6.0 fftw3 alsa dbus-1 gthread-2.0 dbus-glib-1) were
    not met:
  |
  | No package 'dbus-1' found
  | No package 'dbus-glib-1' found

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