Image selection is not properly initialized to none,
and it used before having a chance to have a value.
Due to dynamic nature of Python, variable is used before
it exists, in this case. This causes a crash.
Bug introduced during the fix of [YOCTO #3228]
Fixes [YOCTO #3334]
(Bitbake rev: 1c540541c5397c38dca880a79df9ebfcda576d4c)
Signed-off-by: Cristian Iorga <cristian.iorga@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>