Add support for OpenVPN 2.3.0 status files.

Fix a bug that breaks this module if a server is running multiple instances of OpenVPN and one instance does not have any clients connected.
[perl_openvz] allow simulated plugins to be enabled and disabled
[perl_openvz] use hostname over veid
[perl_openvz] ignore lo interface. report like the real plugin does
[perl_openvz] fix update error
[perl_openvz] rework read_interface
make this a little more perly
typoed ref to hash; copy values
Merge pull request #1 from jyotty/cl/perl-openvz

Cl/perl openvz
[perl_openvz] fix missing semicolon from @jyotty
Add Alias and ConnectTimeout options to MySQL plugin
Included memory usage per VM

Included all the metrics about the actual memory used by VMs (as
returned by libvirt.virDomainMemoryStats)
Drop st_mysql_options and use db->con->options instead
Annotate meta data for db plugins

Provide a MetadataFrom setting to name columns whose content is to be
added as metadata to the data collected.  Similar in usage to the
ValuesFrom setting.
add log_logstash plugin to emit logstash json_event messages.
Add PluginInstanceFormat option to add plugin instance support
curl_json plugin: avoid cache aliasing by using all fields instead of the final two

The following two keys

  Key workers/*/requests
  Key workers/*/apps/*/requests

can both lead to type_instance's of say

  0-requests

which would alias in the cache.  If, instead of just the final two key
name components, we use all of them it would lead to these

  Key workers-0-requests
  Key workers-0-apps-0-requests

which would not overlap.
PUTNOTIF: Add the ability to populate meta options
Applying modifications as requested by octo from GitHub
version-gen.sh: Ensure only collectd repository versions are used

When cross compiling in hosted environments using RPM,
the extracted tar-ball can be located in a parent .git repository.

The version-gen.sh script will then take the version number from
this repository as if it represents collectd.

This can be even more erroneous when the version returned is non
numerical and breaks the build

Signed-off-by: Kieran Bingham <kieran.bingham@st.com>