bug fix: fix mem leak error in vpxenc

fixes memory leak bug in vpxenc.

Change-Id: I3933026d16177947576c61ebf58f8c58147e4ba0

vpxenc.c

@@ -2496,5 +2496,6 @@ int main(int argc, const char **argv_)
 
     vpx_img_free(&raw);
     free(argv);
+    free(streams);
     return EXIT_SUCCESS;
 }