libext2fs: strict inline data overwrite should not return ENOSPC

libext2fs: strict inline data overwrite should not return ENOSPC

If we're doing a strict overwrite (same data size) of data in an
inline data file, we should be able to skip the size check.  If the
in-core EA representation is fine but the on-disk EA is slightly
corrupt (this happens when fixing minor errors in an inline dir), the
ext2fs_xattr_inode_max_size() call, which reads the disk EA, can lead
us to think that there's no space when in reality there is no issue
with doing a strict overwrite.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>