[Samba] SAMBA4: Changing DC's IP address (Bind 9.8.x) for testing

[Adam Tauno Williams]

I upgraded by S3 domain to S4 using the upgrade script.  To do that i
had to have the S4 test box connected to the production network.  Now I
want to take it to the test network.  But the Bind 9.8.x instance using
the DLZ still has the old address... dynamic dns update doesn't work
because the tool can't find the KDC because DNS returns the wrong IP
address.

Can I modify the DNS zone using an ldb tool [ldbmodify]? To change the
IP of the DC (the only address in DNS at this point, everything seems to
CNAME back to the address).

Under the older Bind config I just changed the one or two lines in the
text zone file when I moved the VM from production to testing.