TAKE - fix xfs_repair with separate log devices

[Phil Schwan <phil@xxxxxxxxxxxxx>]

sim_init() was unconditionally setting simargs->logname to NULL.  This
broke external log filesystems.

Modid:  2.3.99pre2-xfs:slinx:58032a

The following file(s) were checked into:
  bonnie.engr.sgi.com:/isms/slinx/2.3.99pre2-xfs
  
cmd/xfs/repair/init.c - 1.9
http://oss.sgi.com/cgi-bin/cvsweb.cgi/linux-2.4-xfs/cmd/xfs/repair/init.c.diff?r1=text&tr1=1.9&r2=text&tr2=1.8&f=h
        - sim_init() was unconditionally setting simargs->logname to
        NULL.  This broke external log filesystems.