f2fs: do not discard data protected by the previous checkpoint
f2fs: do not discard data protected by the previous checkpoint

We should not discard any data protected by the previous checkpoint all
the time.

Signed-off-by: Jaegeuk Kim <71255387a32c360dfbe6dfb7aaeb123bf1dc8cb6@kernel.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs