Refactor #stop to reference ALL_PROCESSES for a bit clearer readability

lib/foreman/engine.rb

@@ -63,7 +63,7 @@ class Foreman::Engine
 
   def stop(name, signal='SIGTERM')
     running_processes.each do |pid, process|
-      unless name.nil?
+      unless name == ALL_PROCESSES
         # Comparing against process.entry.name instead of process.name to
         # make sure we match the process name exactly for any/all
         # concurrently running processes by this name
@@ -104,10 +104,10 @@ private ######################################################################
     return if @terminating
     @terminating = true
     Timeout.timeout(5) do
-      stop(nil)
+      stop ALL_PROCESSES
     end
   rescue Timeout::Error
-    stop(nil, 'SIGKILL')
+    stop(ALL_PROCESSES, 'SIGKILL')
   rescue Errno::ECHILD
   end