Description of problem:
gfs_mkfs doesn't zero out the entire page used for the gfs superblock
and consequently the bytes after the superblock can be anything.
These bits aren't really used for anything, but they look ugly
when viewing with gfs_edit.

Version-Release number of selected component (if applicable):
RHEL5

How reproducible:
Always

Steps to Reproduce:
1. dd if=/dev/urandom of=/dev/trin_vg/trin_lv bs=1M count=16
2. gfs_mkfs -t bob_cluster2:bobs_gfs -p lock_dlm -j 2 /dev/trin_vg/trin_lv
3. gfs_edit /dev/trin_vg/trin_lv
  
Actual results:
Garbage after the superblock structure.

Expected results:
No garbage, rest of the page should be zeroed out.

Additional info:
This data was zeroed for RHEL4, but isn't for RHEL5.
There shouldn't really be any consequences for customers here unless
we decide at a later point in time to reuse some of those bits after
the superblock and include them into the structure.

I checked the other data structures, such as the rgindex, the RGs,
the journal index, etc.  All of them were zeroed properly, so I think
this only affects the one block.

Reported by Abhi Das.  I recreated it on trin-10.
I recommend we fix for RHEL5.1.