staging: lustre: obd: rename LUSTRE_STRIPE_MAXBYTES

Rename LUSTRE_STRIPE_MAXBYTES to LUSTRE_EXT3_STRIPE_MAXBYTES and
correct the comment describing its use.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-2675
Reviewed-on: http://review.whamcloud.com/11800


Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>