Add `nil` default to exit_types, transport param order swap

This allows for checking against exit types to be super easy instead of
having to have extra checks in place. Also changed the order of scope_id
and uri in the transport URI generation. The net effect of this is NOP
because these things only appear separately.

lib/msf/core/payload/windows.rb

@@ -34,10 +34,12 @@ module Msf::Payload::Windows
   #
   @@exit_types =
     {
+      nil       => 0,          # Default to nothing
+      ''        => 0,          # Default to nothing
       'seh'     => 0xEA320EFE, # SetUnhandledExceptionFilter
       'thread'  => 0x0A2A1DE0, # ExitThread
       'process' => 0x56A2B5F0, # ExitProcess
-      'none'    => 0x5DE2C5AA, # GetLastError
+      'none'    => 0x5DE2C5AA  # GetLastError
     }
 
   #

lib/rex/payloads/meterpreter/config.rb

@@ -49,11 +49,7 @@ private
 
   def session_block(opts)
     uuid = to_str(opts[:uuid].to_raw, UUID_SIZE)
-    if opts[:exitfunk]
-      exit_func = Msf::Payload::Windows.exit_types[opts[:exitfunk]]
-    else
-      exit_func = 0
-    end
+    exit_func = Msf::Payload::Windows.exit_types[opts[:exitfunk]]
 
     session_data = [
       0,                  # comms socket, patched in by the stager
@@ -74,8 +70,8 @@ private
     end
 
     url = "#{opts[:scheme]}://#{lhost}:#{opts[:lport]}"
-    url << "?#{opts[:scope_id]}" if opts[:scope_id]
     url << "#{opts[:uri]}/" if opts[:uri]
+    url << "?#{opts[:scope_id]}" if opts[:scope_id]
 
     # if the transport URI is for a HTTP payload we need to add a stack
     # of other stuff