Fix #5761, pass the correct arch and platform for exe generation

Fix #5761

lib/msf/core/exploit/cmdstager.rb

@@ -112,7 +112,8 @@ module Exploit::CmdStager
   def generate_cmdstager(opts = {}, pl = nil)
     select_cmdstager(opts)
 
-    self.exe = generate_payload_exe(:code => pl)
+    exe_opts = { code: pl }.merge!(opts)
+    self.exe = generate_payload_exe(exe_opts)
 
     if exe.nil?
       raise ArgumentError, 'The executable could not be generated'

modules/exploits/linux/http/fritzbox_echo_exec.rb

@@ -108,10 +108,11 @@ class Metasploit3 < Msf::Exploit::Remote
     end
 
     print_status("#{peer} - Exploiting...")
-
     execute_cmdstager(
-      :flavor  => :echo,
-      :linemax => 92
+      flavor: :echo,
+      linemax: 92,
+      platform: target.platform,
+      arch: target.arch
     )
   end
 end