dhcpd, removed unused variable and reformatted

stmt_subclass was a little too cluttered so I changed it to multiple
lines for readability.  I had also introduced an unused lens sep_to_ncl
which I removed.
dhcpd, fix for key block puts

I discovered this after thinking I was done.  It actually was a problem
before I started messing with the code but I didn't notice it because
there was never any test for keys.
dhcpd, fix for put on dhcp option records

Type cannot be blank.  I fixed this by making it use record instead of
nesting through "type"