tar verify_volume() looping fix

[solar]

Hi,

Attached is a patch to a really nasty typo in verify_volume().  The
patch is against tar-1.13.17, but is needed for tar-1.13.19 as well.

(I had this actually happen to my backup yesterday.)  Another bug I
haven't spotted yet resulted in --

tar: home/someone/.netscape/pab.na2: Cannot seek to 32758180202112622: Invalid 
argument
home/someone/.netscape/pab.na2: Could only read 28672 of 2123912 bytes
home/someone/.netscape/pab.na2: Contents differ

-rw-r--r--    1 someone  someone     49152 Nov  7  2000 
/home/someone/.netscape/pab.na2

at about 95% through verification of a 2 GB backup.  The file didn't
change during the backup.  There're no filesystem errors.

-- 
/sd