The signal handler of the 'Base image' combo was still connected during load
such that updating the UI to reflect the loaded base image triggered a change
of the model. Fix this by disconnecting the signal handler when updating the
displayed 'Base image'.
Fixes [YOCTO #1282]
(Bitbake rev: 58036a79cb79d1dff307e2cfed0e684493178507)
Signed-off-by: Joshua Lock <josh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>