generate_name generates bad hostnames

[bigkraig]

  # Generate what should be a unique server name up to 63 total chars
  # Base name:    15
  # Username:     15
  # Hostname:     23
  # Random string: 7
  # Separators:    3
  # ================
  # Total:        63

The problem arises when the name is truncated to end in a . before the -random string is appended. For example:

default-ubuntu-1404-XXXXX-XXXXXXX.XXXXXXX.XXXXX.XXXXXX.-79i6hje

Ideally the function would be smart enough to purge the . before -79i6hje.