Revert "Disable salt master and minions globally"

This reverts commit ec900482c3db820e1f24ba380040d466c35f705f.

The original reason for disabling salt globally was a slow
memory/process leak with the message queue in versions prior to
0.16. Ensuring salt packages are upgraded everywhere should mitigate
the issue.

Change-Id: Ie5cb4df7367d82551b79decf2ba71349df1966d7
Add a Jenkins slave for triggering salt commands

This is the skeleton we'll fill out with any additional
functionality needed by the salt-trigger slave.

Change-Id: I928c2fa4c64e69140b673615a8c18e4eea79e952
Mention the --salt option in launch instructions

Change-Id: I8f8ddc32c2be997bfedd772e8a462837b7a43423
Merge "Revert "Disable salt master and minions globally""
Merge "Add a Jenkins slave for triggering salt commands"
Merge "Mention the --salt option in launch instructions"