unbreak handling of symlinks on Windows

A mistake in the rktio conversion causes a crash if certain functions,
such as `directory-exists?`, are used before certain other functions,
such as `resolve-path`.

Thanks to Alex Harsanyi for the report.

racket/src/rktio/rktio_fs.c

@@ -444,6 +444,7 @@ static int UNC_stat(rktio_t *rktio, const char *dirname, int *flags, int *isdir,
 	}
 
         do {
+	  init_procs();
           if (dest) free(dest);
           dest_len = len + 1;
           dest = malloc(dest_len);