Don't ignore errors in Vm#running_processes

The Vm#running_processes method currently logs all errors/exceptions
instead of raising them up.  This causes the tasks to look like they
were successful even though there are warnings in the log about
mis-configuration which should be corrected by the user.

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1534023

app/models/vm.rb

@@ -76,7 +76,7 @@ def running_processes
  check = validate_collect_running_processes
  unless check[:message].nil?
  _log.warn(check[:message].to_s)
- return pl
+ raise check[:message].to_s
  end
 
  begin