Don't try to trap SIGKILL since it can't be trapped/ignored.

Fixes `appliance_console.rb:105 in `trap': invalid argument - SIGKILL`

Ruby 2.1 and earlier lets you trap SIGKILL even though it's useless.
Ruby 2.2 won't let you try to trap it.

See ManageIQ#2313

[skip ci]

lib/appliance_console.rb

@@ -102,7 +102,7 @@ def agree_with_timeout(*args, &block)
 
 require 'appliance_console/errors.rb'
 
-[:INT, :TERM, :KILL, :ABRT, :TSTP].each { |s| trap(s) { raise MiqSignalError } } if LOCK_CONSOLE
+[:INT, :TERM, :ABRT, :TSTP].each { |s| trap(s) { raise MiqSignalError } } if LOCK_CONSOLE
 
 # Disabled in order to allow rescue of timeout error
 HighLine.track_eof = false