dm log userspace: fix comment hyphens

Fix comments: clustered-disk needs a hyphen not an underscore.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

Documentation/device-mapper/dm-log.txt

@@ -48,7 +48,7 @@ kernel and userspace, 'connector' is used as the interface for
 communication.
 
 There are currently two userspace log implementations that leverage this
-framework - "clustered_disk" and "clustered_core".  These implementations
+framework - "clustered-disk" and "clustered-core".  These implementations
 provide a cluster-coherent log for shared-storage.  Device-mapper mirroring
 can be used in a shared-storage environment when the cluster log implementations
 are employed.

drivers/md/dm-log-userspace-base.c

@@ -146,7 +146,7 @@ static int build_constructor_string(struct dm_target *ti,
  *	<UUID> <other args>
  * Where 'other args' is the userspace implementation specific log
  * arguments.  An example might be:
- *	<UUID> clustered_disk <arg count> <log dev> <region_size> [[no]sync]
+ *	<UUID> clustered-disk <arg count> <log dev> <region_size> [[no]sync]
  *
  * So, this module will strip off the <UUID> for identification purposes
  * when communicating with userspace about a log; but will pass on everything