e2fsck: zap extent-format inode with no extent header

e2fsck: zap extent-format inode with no extent header

The kernel requires all inodes with the extent flag set to have a
valid extent tree header in i_block.  The ext2fs_extent_open2 prefers
to initialize the header if i_block is zeroed, but e2fsck never writes
the new header to disk.  Since the kernel won't create inodes with the
flag and no header anyway, zap such files.

Reported-by: Bo Branten <bosse@acc.umu.se>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>