Add distro check functions for Ubuntu and Fedora

Add is_fedora & is_ubuntu functions, based on names of the checks used
in devstack itself.

Change-Id: I60763d5655344dd008f307b1caad8776277afb3b
Clean up sudoers archive

Group and comment archive of sudoers

Change-Id: I2713d636b9d979153cb6e5adf90a7927d2d51401
Check for rabbitmq before archiving

Don't assume rabbitmq related files exist

Change-Id: I7bd9e92824bc3cc5d736aee004c02724e213a903
Merge "Clean up sudoers archive"
Merge "Add distro check functions for Ubuntu and Fedora"