server: Cleanup dhcp and dns entries only on expunging VM

[yadvr]

This fixes a behaviour to not cleanup DHCP and DNS rules for NICs of a
VM in the VR when it is stopped, but instead when VM is expunged because
stopped VMs in CloudStack still retain the IPs and records.

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)

[yadvr]

@blueorangutan package

[blueorangutan]

@rhtyd a Jenkins job has been kicked to build packages. I'll keep you posted as I make progress.

[blueorangutan]

Packaging result: ✔centos6 ✔centos7 ✔debian. JID-290

[yadvr]

@blueorangutan test

[blueorangutan]

@rhtyd a Trillian-Jenkins test job (centos7 mgmt + kvm-centos7) has been kicked to run smoke tests

[anuragaw]

LGTM from code.

[shwstppr]

LGTM on changes!
Although dhcp cleanup on VM stop seems more logical to me.

[nvazquez]

LGTM, this makes cleanup introduced in this PR: #3351 to be performed only on VM expunge

[wido]

LGTM based on code

[yadvr]

FYI - this partially reverts and refactors changes introduced in #3351 to cleanup VM dhcp/dns rules in the VR only when a VM is expunged. A VM hostname and IP address is used as constraint and checks even of a VM is stopped, i.e. you cannot deploy a VM with the same hostname and IP in a network with an existing VM with those attributes. This was tested against a local monkeybox KVM env and regression tested agains Trillian/kvm.