nandroid: Allow tar backups of yaffs2 partitions

Change-Id: I33dca9864b043527640c6586751c9399bc3fb156
clean up unused variables and fix compiler warnings

Change-Id: I3c3e30d5e27706d59be78ec935e8a095ba4ab0c0
Merge branch 'cm-11.0' of github.com:CyanogenMod/android_bootable_recovery into cm-11.0