LU-5543 ldiskfs: export ldiskfs_map_blocks

LU-5543 ldiskfs: export ldiskfs_map_blocks

Regression caused by reccnt commit
31190547864cbcac1f6b85e88fd129dfe7de0977.  Seen only in sles11sp3 as
it requires a server build on a 3.0 or later kernel to make it happen.
sles11sp3 is the only currently supported distro where that is true.

New code in osd-ldiskfs that is conditional when
HAVE_LDISKFS_MAP_BLOCKS is set by autoconf calls ldiskfs_map_blocks.
That entry point exists in ext4/ldiskfs code, but isn't exported with
EXPORT_SYMBOL.  This causes a runtime failure at module load time of
osd-ldiskfs with an error like:

osd_ldiskfs: Unknown symbol ldiskfs_map_blocks (err 0)

This mod adds the needed EXPORT_SYMBOL() to an ldiskfs patch.

Test-Parameters: mdsdistro=sles11sp3 ossdistro=sles11sp3 clientdistro=sles11sp3 mdsfilesystemtype=ldiskfs mdtfilesystemtype=ldiskfs ostfilesystemtype=ldiskfs
Signed-off-by: Bob Glossman <bob.glossman@intel.com>
Change-Id: I0722bfaf73d736247f07d5402aea05dadcfcd394
Reviewed-on: http://review.whamcloud.com/11591
Tested-by: Jenkins
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Minh Diep <minh.diep@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>