libblkid: fix limit for OCFS check

libblkid: fix limit for OCFS check

Rogier Goossens wrote:

 While testing KDE partitionmanager, I discovered that blkid did not
 detect the test OCFS2 filesystem I created. After some investigation,
 it appeared that it will assume the filesystem cannot be OCFS2 if
 smaller than 108M. However, mkfs.ocfs2 from ocfs2-tools (1.6.3) will
 happily create filesystems that are much smaller, only failing below
 approx. 15000 1k blocks, and below approx. 6000 4k blocks.

Reported-by: Rogier Goossens <goossens.rogier@gmail.com>
Signed-off-by: Karel Zak <kzak@redhat.com>