Correct os_version's lucid/precise version numbers

Change-Id: I174bdb8cee116ffe72b2e2fa7762a58c605d6ba8
diamond: install python-statsd on >= precise

Retry commit 2d3f3cbc3824416b3cdf4d59ce43b8ab9d16eadb, this time
removing the require => Class dependency as well. The dependency could
be added inside the conditional, but since require_package effectively
adds a "require package::python_statsd" it's superfluous anyway (this is
documented in require_package too).

Change-Id: I6f9fa40d80f6e2d9cf51dc01a6e5d7ad3191fa0d