pp: Fix memory leak on error path.

Fixes Coverity resource leak defect.

Reviewed-by: José Fonseca <jfonseca@vmware.com>

src/gallium/auxiliary/postprocess/pp_program.c

@@ -41,12 +41,13 @@ struct program *
 pp_init_prog(struct pp_queue_t *ppq, struct pipe_screen *pscreen)
 {
 
-   struct program *p = CALLOC(1, sizeof(struct program));
+   struct program *p;
 
    pp_debug("Initializing program\n");
    if (!pscreen)
       return NULL;
 
+   p = CALLOC(1, sizeof(struct program));
    if (!p)
       return NULL;