[ruby/zlib] Revert "Don't print out warnings when freeing."

https://github.com/ruby/zlib/commit/931aa7a272

ext/zlib/zlib.c

@@ -1226,6 +1226,17 @@ zstream_finalize(struct zstream *z)
 	finalizer_warn("the stream was freed prematurely.");
 }
 
+static void
+zstream_free(void *p)
+{
+    struct zstream *z = p;
+
+    if (ZSTREAM_IS_READY(z)) {
+	zstream_finalize(z);
+    }
+    xfree(z);
+}
+
 static size_t
 zstream_memsize(const void *p)
 {
@@ -1235,7 +1246,7 @@ zstream_memsize(const void *p)
 
 static const rb_data_type_t zstream_data_type = {
     "zstream",
-    { zstream_mark, xfree, zstream_memsize, },
+    { zstream_mark, zstream_free, zstream_memsize, },
      0, 0, RUBY_TYPED_FREE_IMMEDIATELY
 };