Merge pull request #163 from elasticsearch/new_centos_image

[TESTING] Make use of new centos image
Add check for listing all logstash processes
Fix typo
Messed up the test
Remove failing tests
[TESTING] replace stdout ouput with null

Sometimes LS hangs which could be caused by the stdout output.
Replacing this with the null output should fix this.
[TESTING] pin gem versions to solve issues
[TESTING] Add ubuntu 14.04 docker container
[TESTING] Avoid installing rubygems
[TESTING] Add more checks so we can see how many processes are running.
[TESTING] Fix test
[TESTING] Add more process related tests

We see sometimes that there are 2 processes running while that shouldn't happen.
[TESTING] Add some sleep times in there to avoid to fast restarts

In some cases we don't give Logstash time enough to do its thing to start up
resulting in weird duplicate processes.
This commit should fix that
[TESTING] Test fails on PE installs

forgot to that PE uses java for puppetdb so can't check for the name 'java'
[TESTING] implement proxy for downloads
[TESTING] Avoid proxy for localhost
[TESTING] Try to fix the no_proxy option

Some PE setups still fail
[TESTING] Use http only for urls

https urls can't be cached