MMFMWK-8402 glcolorbalance: fix pipeline crash when init

caps should be copied in gcb_transform_internal_caps,
ownership is not passed to the function

upstream status: backport[1.14.4]
https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/issues/546

ext/gl/gstglcolorbalance.c

diff --git a/ext/gl/gstglcolorbalance.c b/ext/gl/gstglcolorbalance.c
index 26c51e8..f448e9b 100644
--- a/ext/gl/gstglcolorbalance.c
+++ b/ext/gl/gstglcolorbalance.c
@@ -181,7 +181,7 @@
 gcb_transform_internal_caps (GstGLFilter * filter,
     GstPadDirection direction, GstCaps * caps, GstCaps * filter_caps)
 {
-  GstCaps *tmp = gst_caps_make_writable (caps);
+  GstCaps *tmp = gst_caps_copy (caps);
   gint i;
   /* If we're not in passthrough mode, we can only output 2D textures,
    * but can always receive any compatible texture.