(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
maint - readd sbins to install.rb

c4cc67 culled sbins when it should have edited it.
maint - further fix for debian packaging
Unbreak after mc-call-agent removal
Merge pull request #192 from jasperla/packaging

Unbreak after mc-call-agent removal
(MCO-186) Change url in solaris readme

This commit changes to broken codehaus.org url to refer to rubygems
instead.
Merge pull request #193 from ploubser/bug/master/mco-186

(MCO-186) Change url in solaris readme
MCO-325 - update win32 instructions to point at 1.9.3

MCollective runs acceptably well on 1.9.3 on windows.  It's what
we ship in PE and also what the unofficial .msi uses.
Merge pull request #194 from richardc/MCO-325_windows_readme

MCO-325 - update win32 instructions to point at 1.9.3
(MCO-311) Remove current directory from Ruby load path

Conflicts:
	bin/mc-call-agent
(MCO-346) - Fix Data plugin and Agent load ordering

In 2.5.0 the rewrite of the runnner class the load ordering of Data
plugins and Agents were changed around. This causes Data plugins that
depend on agents like for example activate_when{PluginManager['service_agent']}

This commit restores the order.
Merge pull request #197 from ploubser/bug/stable/MCO-346

(MCO-346) - Fix Data plugin and Agent load ordering
MCO-336 - update release notes and changelog for 2.5.2
(maint) Update release date
Merge pull request #4 from melissaanne/maint/update_notes_changelog

Maint/update notes changelog
Merge branch 'MCO-311/2.5.1/security_fixes' into stable

* MCO-311/2.5.1/security_fixes:
  (maint) Update release date
  MCO-336 - update release notes and changelog for 2.5.2
  (MCO-311) Remove current directory from Ruby load path
Merge branch 'stable'

* stable:
  (maint) Update release date
  MCO-336 - update release notes and changelog for 2.5.2
  (MCO-346) - Fix Data plugin and Agent load ordering
  (MCO-311) Remove current directory from Ruby load path