(MCO-262) Improve line parsing in flatfile discovery

In the past flatfile discovery would fail if a line started started or
ended with whitespaces or if a empty line was encountered.

This commit softens the definition of what a valid line is by now
stripping leading and trailing whitespace characters before validating
the line with the regular expression.

Empty lines and lines starting with the comment character # will now
also be skipped.
Merge pull request #184 from ploubser/bug/master/mco-262

(MCO-262) Improve line parsing in flatfile discovery
(MCO-266) Stop installing mc-call-agent

The code paths used to implement mc-call-agent has been deprecated since
2.2.0.

This commit removes the mc-call-agent script and all its references in
the packaging code.
Merge pull request #185 from ploubser/bug/master/mco-266

(MCO-266) Stop installing mc-call-agent
(docs) Update Vagrant download link

The current Vagrant downloads live at a different page now.
Merge pull request #186 from nfagerlund/docs_vagrant_link

(docs) Update Vagrant download link
MCO-285 Fix for `mco plugin package` on RedHat variants

The plugin application failed to include the RedHat label to
the package name.

This commit fixes the above issue by correctly adding the
version label to the package name; we now assume that the
label always starts with a dot, as documented in:
http://fedoraproject.org/wiki/Packaging:DistTag#Possible_values_for_.25.7Bdist.7D

Also, to make more robust the way we retrieve the list of
packages paths, we now use glob for both the rpmdir and srpmdir
directories and replace the label part of the file name with a
wildcard.

The fix was based on the patch suggested by Daniel Schleenzig.
Merge pull request #187 from parisiale/MCO-285

MCO-285 Fix for `mco plugin package` on RedHat variants
MCO-292 Fix for `missing dist macro` for RedHat packages

The plugin application incorrectly set package dependencies for RedHat
variants; as a consequence, rpm failed to install the built packages.

This change fixes the above issue (regression of MCO-285) by adding the
release label (e.g. ".el6") to package dependencies.
Tested on a CentOS box by installing mcollective-process-agent.
Merge pull request #189 from parisiale/MCO-292

MCO-292 Fix for `missing dist macro` for RedHat packages
Add RabbitMQ clustering setup instructions.
Merge pull request #188 from daenney/docs-rabbitmq-clustering

Add RabbitMQ clustering setup instructions.
(MCO-316) Allow username/password to be unspecified

In an environment where a user wants to set up authentication based
on client certificates, the current behavior of insisting on a
login/passcode being supplied falls down.

For rabbitmq especially this inhibits client certificate authentication
from working: https://www.rabbitmq.com/stomp.html#cta.ssl

    "Clients must not supply login and passcode headers."

Here we make the login/passcode optional and defaulting to '', which the stomp
gem takes to mean 'unspecified':

    https://github.com/stompgem/stomp/blob/v1.3.2/lib/connection/netio.rb#L354-L355

Note: for this to be effective you will need to use a stomp gem >=
1.3.2, as the behaviour of not passing login/passcode was fixed for
1.3.0 with this commit:

    https://github.com/stompgem/stomp/commit/7060e740a4e1ac3f3dd7a45a884bdbe5eb10ddc3
Merge pull request #190 from richardc/MCO-316_rabbitmq_certificates

(MCO-316) Allow username/password to be unspecified
(MCO-300) Update changelog and releasenotes for 2.5.1
Merge pull request #191 from richardc/MCO-300.changelog_release_notes

(MCO-300) Update changelog and releasenotes for 2.5.1