Land rapid7#4425, jobs tab completion NilClass fix

Author: wvu

lib/msf/ui/console/command_dispatcher/core.rb

@@ -873,7 +873,7 @@ def cmd_jobs_tabs(str, words)
       return @@jobs_opts.fmt.keys
     end
 
-    if @@jobs_opts.fmt[words[1]][0] and (words.length == 2)
+    if words.length == 2 and (@@jobs_opts.fmt[words[1]] || [false])[0]
       return framework.jobs.keys
     end