GCP: Remove requirement for TARGET-INSTANCE object in AliasIP only use case

[alaari-f5]

(Issue moved from: f5devcentral/f5-cloud-failover-extension#15)
Reported by: @f5-applebaum

Use case is that you would like to failover only AliasIps (vs Forwarding Rules).

Currently, the failover requires TARGET_INSTANCE objects to be created which is only needed for Forwarding Rules.

Workaround is creating target instance objects:

https://cloud.google.com/sdk/gcloud/reference/compute/target-instances/create

gcloud compute target-instances create NAME --instance=INSTANCE [--description=DESCRIPTION] [--instance-zone=INSTANCE_ZONE] [--zone=ZONE] [GCLOUD_WIDE_FLAG …]

[alaari-f5]

This is being tracked internally as:

AUTOSDK-195 - GCP: Remove requirement for TARGET-INSTANCE object in AliasIP only use case

[shyawnkarim]

Closing. This issue was resolved with release 1.2.