Fix make_normalpath() with trailing backslash

There was an ambiguous code there:

- if the path had trailing backslash and existed => return "<path>\"
- if the path didn't have trailing backslash and existed => return "<path>\"
- if the path had trailing backslash and didn't exist => return "<path>\"
- if the path didn't have trailing backslash and didn't exist => return "<path>"

This can have two interpretations:

- if the path doesn't exist, don't change its trailing backslash
  presence, otherwise always return with trailing backslash

- no matter what, always return path with trailing backslash and the
  code is buggy

I'm choosing the second one as it adds consistency and simplifies caller
code. QED's (which is from the same author as CF-Lib) usage of this
function seems to support this intent.

Author: mikrosk

fsnorm.c

@@ -90,9 +90,8 @@ int make_normalpath(char *path)
 	}
 
 	ret = path_exists(p);
-	if (!ret)
-		p[i] = '\0';
 
+	/* always return path with trailing backslash */
 	strcpy(path, p);
 	return ret;
 }