Cleaned up double-negative logic.

Decreased default HTTPClientTimeout to 5 seconds.

modules/exploits/linux/http/efw_chpasswd_exec.rb

@@ -110,7 +110,7 @@ class Metasploit4 < Msf::Exploit::Remote
 
     register_advanced_options(
       [
-        OptInt.new('HTTPClientTimeout', [ true, 'HTTP read response timeout (seconds)', 10])
+        OptInt.new('HTTPClientTimeout', [ true, 'HTTP read response timeout (seconds)', 5])
       ], self.class)
 
   end
@@ -173,13 +173,11 @@ class Metasploit4 < Msf::Exploit::Remote
         'data' => data
       })
 
-     if not res.nil?
-      if res.code == 404
+     if res && res.code == 404
        fail_with(Failure::Unreachable,
          "#{rhost}:#{rport} - Received a 404 HTTP response - " +
          "your TARGETURI value is most likely not correct")
      end
-     end
 
   end