The version_id isn't set during add_node() call. This function is called
when introspection starts for both "new" and existing node_info records.
As a result, race conditions can appear in an HA inspector deployment (see
the refered bug).
This patch makes sure a version_id is generated during the add_node() call
so stale record updates can be detected through the version_id mismatch
between the inspector memory and the DB record.
Change-Id: I422473e888e5e49abb3e598fc2cf2f330620bdcd
Closes-Bug: #1719627