def find_sbin(cmd)
      path = SBIN_PATHS.detect do |dir|
        File.exists?(File.join(dir, cmd))
      end

      raise RightScale::LoginManager::SystemConflict, "Failed to find a suitable implementation of '#{cmd}'." unless path

      File.join(path, cmd)
    end
def find_sbin(cmd)
      path = SBIN_PATHS.detect do |dir|
        File.exists?(File.join(dir, cmd))
      end

      raise RightScale::LoginManager::SystemConflict, "Failed to find a suitable implementation of '#{cmd}'." unless path

      File.join(path, cmd)
    end
Search through some directories to find the location of a binary. Necessary because different
 Linux distributions put their user-management utilities in slightly different places.

 === Parameters
 cmd(String):: name of command to search for, e.g. 'usermod'

 === Return
 path(String):: the absolute path to the command

 === Raise
 (LoginManager::SystemConflict):: if the command can't be found