Dont try to close non-existent fdno's on Fclose()

- Commit 547a004 introduced a regression
  on stacked io Fclose() return code, details at
  http://lists.rpm.org/pipermail/rpm-maint/2014-August/003731.html
- The original code seems fishy in other ways (missed errors), this
  hopefully fixes both cases by only attempting to close actually
  open fdno's and only considering actual closes for error codes.

(cherry picked from commit 0ffc0e2)

rpmio/rpmio.c

@@ -1028,16 +1028,18 @@ int Fclose(FD_t fd)
     fd = fdLink(fd);
     fdstat_enter(fd, FDSTAT_CLOSE);
     for (FDSTACK_t fps = fd->fps; fps != NULL; fps = fdPop(fd)) {
-	fdio_close_function_t _close = FDIOVEC(fps, close);
-	rc = _close ? _close(fps) : -2;
+	if (fps->fdno >= 0) {
+	    fdio_close_function_t _close = FDIOVEC(fps, close);
+	    rc = _close ? _close(fps) : -2;
+
+	    if (ec == 0 && rc)
+		ec = rc;
+	}
 
 	/* Debugging stats for compresed types */
 	if ((_rpmio_debug || rpmIsDebug()) && fps->fdno == -1)
 	    fdstat_print(fd, fps->io->ioname, stderr);
 
-	if (ec == 0 && rc)
-	    ec = rc;
-
 	/* Leave freeing the last one after stats */
 	if (fps->prev == NULL)
 	    break;