[GST1.14] Update configurea.ac for bad-base

- As there is no bad base lib in GST1.14
  no need to return error to stop configue

Signed-off-by: Lyon Wang <lyon.wang@nxp.com>
diff --git a/configure.ac b/configure.ac
index 4061920..080e145 100755
--- a/configure.ac
+++ b/configure.ac
@@ -191,7 +191,7 @@
 
 dnl Give a warning if we don't have gstreamer libs
 if test "x$HAVE_GST_BAD_BASE" = "xno"; then
-  AC_MSG_ERROR(no GStreamer bad-base found)
+  AC_MSG_WARN(no GStreamer bad-base found)
 fi
 
 dnl make GST_BAD_BASE_CFLAGS and GST_BAD_BASE_LIBS available