Adds IPv6 url validation support

Fixes an issue where url validation fails when attempting to
create an endpoint with an IPv6 address in the URL.

Change-Id: I179b0cb7e5546a3a051e5a1e6390385a833b9f96
Closes-Bug: 1386376
(cherry picked from commit 7fa6e92c441644c0d990e79a78692b786d88acec)
Merge "Adds IPv6 url validation support" into stable/juno