DO NOT MERGE - f2fs-tools: ensure that unused xattr space is zeroized

Also add a missing free() to fix a memory leak.

Bug: 305658663
Test: - On kernel with bug:
          - Created an f2fs filesystem
          - Created 250-byte xattr on a directory
          - Deleted the xattr
      - Ran fsck.f2fs -f
      - Mounted filesystem
      - On kernel without bug:
          - Created 200-byte xattr on the directory
          - Listed xattrs
      The last step shows corruption before this change, but not after it.
Signed-off-by: Eric Biggers <ebiggers@google.com>
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:f7c0ca9f8b02cbb199d0277c8aefb5098df9a867)
Merged-In: I5ae77803113683887b3aaec804a0547ceb3d80c4
Change-Id: I5ae77803113683887b3aaec804a0547ceb3d80c4
1 file changed