Use get_my_ipv4 from oslo.utils

Remove _get_my_ip from ironic and replace it's usages
by usages of get_my_ipv4 from netutils, because this methods
implements the same functionality.

Change-Id: I85b75f26051170c0d306ef38b517cc1657e47a99
Reuse methods from netutils

Replace usages of is_valid_ipv4, is_valid_ipv6 from Ironic,
by usages of this methods from oslo.utils and remove these
methods from Ironic code.

Change-Id: I5f2b50718f2d6ae2258a14055ddd77fc40d8a344
Merge "Use get_my_ipv4 from oslo.utils"