odhcpd: update to git HEAD version (FS#635)

3d9f406 rework IPv6 dns address selection (FS#635)
bc6c3ac ndp: keep an exact copy of IPv6 interface addresses
6eb1e01 ndp: code cleanup
eea7d03 rework IPv6 address dump logic
24d21c7 ndp: add syslog debug tracing

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>