Fix uninstall error on debian (port to .SPEC)

Because of "set -e", we need to test if cf-* processes are running before
killing them, otherwise postrm fails and we cannot uninstall the package.
Merge pull request #140 from CedricCabessa/contrib

Fix uninstall error on debian (port to .SPEC)
Fixes  #4014: Use the right logrotate file on RHEL systems for rudder-server-root
Merge branch 'branches/rudder/2.4' into branches/rudder/2.6
Merge branch 'branches/rudder/2.6' into branches/rudder/2.7
Fixes #3995 - Add backup of cron file rudder-agent (again!) into rudder-agent preinst
Merge pull request #149 from nperron/bug_3995/int/prevent_from_removing_init_default_and_cron_file_of_rudder_agent_AGAIN

Fixes #3995 - Add backup of cron file rudder-agent (again!) into rudder-agent preinst
Merge pull request #147 from Kegeruneku/bug_4014/int/4014_use_rhel_logrotate_in_rudder_server_root

Fixes  #4014: Use the right logrotate file on RHEL systems for rudder-se...
Merge branch 'branches/rudder/2.4' into branches/rudder/2.6
Merge branch 'branches/rudder/2.6' into branches/rudder/2.7
Merge branch 'branches/rudder/2.7'