Just use a straight RPORT, don't sneak 593.

Incidentally, the endmap scanner doesn't appear to work at all for
http-rpc-epmap, so no harm done anyway (tested against Windows 2008
server).

It looks like a bigger change than it realy is, thanks to the indentaton
changes by removing the itertor. Diff this without whitespace changes to
get a better idea of what's actually different.

lib/msf/core/exploit/dcerpc_epm.rb

@@ -43,10 +43,8 @@ module Exploit::Remote::DCERPC_EPM
     print_status("Connecting to the endpoint mapper service...")
     begin
       eps   = nil
-      dport = nil
+      dport = datastore['RPORT'] || 135
 
-      [datastore['RPORT'], 135, 593,].uniq.each do |i|
-        dport = i
       begin
         eps = Rex::Socket::Tcp.create(
           'PeerHost'  => rhost,
@@ -58,12 +56,8 @@ module Exploit::Remote::DCERPC_EPM
             'MsfExploit' => self,
           }
         )
-
-          break
-
       rescue ::Exception
       end
-      end
 
       if (not eps)
         print_status("Could not connect to the endpoint mapper service")