Pass service name in env to the encoders

Author: agix

modules/exploits/windows/smb/psexec.rb

@@ -165,6 +165,7 @@ def powershell_installed?
   end
 
   def powershell
+    ENV['MSF_SERVICENAME'] = datastore['SERVICE_NAME']
     command = cmd_psh_payload(payload.encoded, payload_instance.arch.first)
 
     if datastore['PSH::persist'] and not datastore['DisablePayloadHandler']