jflteatt: Support potential dev phones

Add support for phones with unlocked boot loaders that do not
require Loki.  Current implementation will not install a boot
image at all unless the phone is a known Loki phone.  This alters
the behavior to flash a stock boot image when we know the
boot loader supports it.

Change-Id: Ifb992696a1f3f870d4fdd1945a943e427269ead7
Merge branch 'cm-10.1' of https://github.com/CyanogenMod/android_device_samsung_jflteatt into HEAD