[HFX-959] XOP-435: Allow clearing of DNS entries.

Signed-off-by: Siddharth Vinothkumar <siddharth.vinothkumar@citrix.com>
Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
Merge pull request #1624 from robhoes/dns-sp1

[HFX-959] XOP-435: Allow clearing of DNS entries.