ODROID: Change the prefix of image file to 'odroid-*'

This patch changes the prefix of image file to start with 'odroid-*'.

Signed-off-by: Dongjin Kim <tobetter@gmail.com>
ODROID: remove --bootstrap-flavour option

'--bootstrap-flavour' option is deprecated

Signed-off-by: Dongjin Kim <tobetter@gmail.com>
ODROID: Add BUILD_NUMBER of Jenkins

This patch is to add BUILD_NUMBER if Jenkins is building the image.

Signed-off-by: Dongjin Kim <tobetter@gmail.com>