Forgetting about Windows for a second...

Repro:

```
wvu@kharak:~/metasploit-framework$ git diff
diff --git a/tools/msftidy.rb b/tools/msftidy.rb
index 1fdad36..224ee61 100755
--- a/tools/msftidy.rb
+++ b/tools/msftidy.rb
@@ -79,7 +79,7 @@ class Msftidy
   ##
 
   def check_mode
-    unless (@stat.mode & 0111).zero?
+    if File.executable?(@full_filepath)
       warn("Module should not be marked executable")
     end
   end
wvu@kharak:~/metasploit-framework$ chmod go+x modules/exploits/windows/smb/ms08_067_netapi.rb 
wvu@kharak:~/metasploit-framework$ ll !$
ll modules/exploits/windows/smb/ms08_067_netapi.rb
-rw-rwxr-x 1 wvu wvu 38410 Nov  5 12:45 modules/exploits/windows/smb/ms08_067_netapi.rb
wvu@kharak:~/metasploit-framework$ tools/msftidy.rb !$
tools/msftidy.rb modules/exploits/windows/smb/ms08_067_netapi.rb
wvu@kharak:~/metasploit-framework$ !chmod:s/go/u/
chmod u+x modules/exploits/windows/smb/ms08_067_netapi.rb 
wvu@kharak:~/metasploit-framework$ ll !$
ll modules/exploits/windows/smb/ms08_067_netapi.rb
-rwxrwxr-x 1 wvu wvu 38410 Nov  5 12:45 modules/exploits/windows/smb/ms08_067_netapi.rb
wvu@kharak:~/metasploit-framework$ !?msftidy
tools/msftidy.rb modules/exploits/windows/smb/ms08_067_netapi.rb
modules/exploits/windows/smb/ms08_067_netapi.rb - [WARNING] Module should not be marked executable
wvu@kharak:~/metasploit-framework$ git reset --hard
HEAD is now at bcc9c76 Add +x check to msftidy
wvu@kharak:~/metasploit-framework$ !?go+x
chmod go+x modules/exploits/windows/smb/ms08_067_netapi.rb 
wvu@kharak:~/metasploit-framework$ ll !$
ll modules/exploits/windows/smb/ms08_067_netapi.rb
-rw-rwxr-x 1 wvu wvu 38410 Nov  5 13:15 modules/exploits/windows/smb/ms08_067_netapi.rb
wvu@kharak:~/metasploit-framework$ !?msftidy
tools/msftidy.rb modules/exploits/windows/smb/ms08_067_netapi.rb
modules/exploits/windows/smb/ms08_067_netapi.rb - [WARNING] Module should not be marked executable
wvu@kharak:~/metasploit-framework$ 
```

So, ```File.executable?``` doesn't do anything about ```go+x```, just ```u+x```.