fix clip close crash

rendering/renderfunctions.cpp

@@ -565,6 +565,8 @@ GLuint compose_sequence(ComposeSequenceParams &params) {
 
                   }
 
+                  qDebug() << "Input colorspace:" << input_cs;
+
                   try {
                     OCIO::ConstProcessorRcPtr processor = config->getProcessor(input_cs.toUtf8(),
                                                                                OCIO::ROLE_SCENE_LINEAR);

timeline/clip.cpp

@@ -498,8 +498,10 @@ void Clip::Close(bool wait) {
     }
 
     // destroy opengl texture in main thread
-    QOpenGLContext::currentContext()->functions()->glDeleteTextures(1, &texture);
-    texture = 0;
+    if (texture > 0) {
+      QOpenGLContext::currentContext()->functions()->glDeleteTextures(1, &texture);
+      texture = 0;
+    }
 
     // close all effects
     for (int i=0;i<effects.size();i++) {