bitbake: toaster: move bldcontrol initial_data fixture to code

bitbake: toaster: move bldcontrol initial_data fixture to code

We move the initial_data fixture to a code migration,
in order to make sure that we don't overwrite modified data.

The data is inserted only if no data is present, instead
of always overwriting the entry.

The check settings returns 0 if the check was ok.

(Bitbake rev: 525c316ac95c06c52fbcfc836ca5599ee9dbfe8b)

Signed-off-by: Alexandru DAMIAN <alexandru.damian@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>