Bug 1044967: Don't create SD card partition for Flame devices

The build scripts don't work on Debian Wheezy, because mkfs.vfat is
either hidden from regular users and/or doesn't work correctly.

This patch disables the creation of an image for the SD card partition,
for which mkfs.vfat is required.
Merge pull request #42 from tdz/bug-1044967

Bug 1044967: Don't create SD card partition for Flame devices