Fix version check for the entry added in r372686.

4.11.14 is not in ports yet, the fix was backported to 4.11.13 so we are
safe with 4.11.13_1.
Unbreak
Fix with non standard PREFIX too
Actually make if_packets_ work.

PR:		194733
Submitted by:	Claudius Herder
Sponsored by:	Absolight
The Sigar API provides a portable interface for gathering system information
such as:

* System memory, swap, cpu, load average, uptime, loginsi
* Per-process memory, cpu, credential info, state, arguments, environment,
  open files
* File system detection and metrics
* Network interface detection, configuration info and metrics
* TCP and UDP connection tables
* Network route table

This information is available in most operating systems, but each OS has their
own way(s) providing it.  SIGAR provides developers with one API to access this
information regardless of the underlying platform.  The core API is implemented
in pure C with bindings currently implemented for Java, Perl, Ruby, Python,
Erlang, PHP and C#.

WWW: https://support.hyperic.com/display/SIGAR/Home