mender-sdimg: replace SDIMG_ with MENDER_ in variable names
mender-sdimg: replace SDIMG_ with MENDER_ in variable names

Use of a deprecated SDIMG_* variable results in a fatal error.

Fixes [Mender #629]

Signed-off-by: Maciej Borzecki <f609d9f713abcd5f8f0e51f08dc151638a7681e7@rndity.com>

bboozzoo/meta-mender,bboozzoo/meta-mender,bboozzoo/meta-mender,bboozzoo/meta-mender