Fix vram leak for reals

src/capture/nvfbc.c

@@ -492,6 +492,7 @@ gsr_capture* gsr_capture_nvfbc_create(const gsr_capture_nvfbc_params *params) {
         .tick = gsr_capture_nvfbc_tick,
         .should_stop = NULL,
         .capture = gsr_capture_nvfbc_capture,
+        .capture_end = NULL,
         .destroy = gsr_capture_nvfbc_destroy,
         .priv = cap_nvfbc
     };