libcli/nbt: fix wack timeout handling

libcli/nbt: fix wack timeout handling

If the client gets a WACK response, the server
sends a timeout to the client. Possible
values are between 9 and 105 seconds.

Because w2k3 servers have a bug and always return
a value of 5 seconds, we need a workarround.

Always using a fixed value of 30 seconds is bad
as we could timeout to early.

Now we use the value from the server if it's in the
valid range and otherwise we use the upper limit
of the valid range (105s).

metze
(from samba4wins tree 40ef7739f4141598a6392c203e4a2d52d972fe06)