cmd: terminate efidebug test bootmgr early on error

If efi_bootmgr_load() fails, there is no point in trying to start an image
that has not been loaded.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
1 file changed