Correctly free config file names

We call xf86penConfigDirFiles twice, so we overwrite the configDirPath
variable, losing the pointer. If we move the pointer management to the
upper layer (the function callers), they will be able to call these
functions as many times as they want, but they'll have to free those
returned values.

v2: don't leak inside XWin

4,097 bytes in 1 blocks are definitely lost in loss record 625 of 632
   at 0x4C2779D: malloc (in vgpreload_memcheck-amd64-linux.so)
   by 0x4D7899: DoSubstitution (scan.c:615)
   by 0x4D87B0: OpenConfigDir (scan.c:845)
   by 0x4D8A2D: xf86openConfigDirFiles (scan.c:955)
   by 0x49031F: xf86HandleConfigFile (xf86Config.c:2327)
   by 0x49A9BF: InitOutput (xf86Init.c:365)
   by 0x425A7A: main (main.c:204)

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Dan Nicholson <dbn.lists@gmail.com>

hw/xwin/winconfig.c

@@ -117,7 +117,7 @@ Bool
 winReadConfigfile ()
 {
   Bool		retval = TRUE;
-  const char	*filename, *dirname;
+  char		*filename, *dirname;
   MessageType	filefrom = X_DEFAULT;
   MessageType	dirfrom = X_DEFAULT;
   char		*xf86ConfigFile = NULL;
@@ -169,6 +169,8 @@ winReadConfigfile ()
     {
       return FALSE;
     }
+  free(filename);
+  free(dirname);
   if ((g_xf86configptr = xf86readConfigFile ()) == NULL)
     {
       winMsg (X_ERROR, "Problem parsing the config file\n");