If getcwd() fails in dinit(), the stat buffer 'swd' is used

If getcwd() fails in dinit(), the stat buffer 'swd' is used
uninitialized by the else clause.  Since it is used in both clauses
we should perform the stat before the if().  However, fixing this
causes 'cp' to be unitialized in some case so initialize cp to NULL
and move the "cp == NULL" check out of the first if() clause now
that it can be true in either case.  OK miko@ deraadt@