add fix_auth --v2 to fix bad/changed v2_keys

If a user wants to secure a manageiq appliance with a preshipped v2_key, they will need to fix any data already in the database. Even a blank database has a token in there.

Currently, `fix_auth.rb` will not clear out passwords encrypted with a lost `v2_key`. This code allows the admin to clear out those values and access the 

- don’t hardcode session token (pick a random one instead)

https://bugzilla.redhat.com/show_bug.cgi?id=1148590
Maybe we could use << operator to combine some of the common strings in the if/else conditions

I don't know, I don't really like either way.  :cry:  Feel free to say, no ;-)

```ruby
def selection_criteria(v2_also = false)
  available_columns.collect do |column|
    sql = "(COALESCE(#{column},'') <> ''"
    if v2_also
      sql << ")"
    else
      sql << " AND #{column} !~ 'v2:\{[^\}]*\}')"
    end
  end.join(" OR ")
end
```