Restore GARP by default for floating IPs

Restore the default value of the send_arp_for_ha configuration
parameter to 3. This parameter was set to 0 by default to
prevent kernel crashes due to bug 1273386.

Change-Id: Idbdc6ff687734776ede45127878af6ad9b8b3ca1
Closes-Bug: 1317834
Merge "Restore GARP by default for floating IPs"