python-tornado: add zlib run-time dependency

Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/python-tornado/Config.in

@@ -1,6 +1,7 @@
 config BR2_PACKAGE_PYTHON_TORNADO
 	bool "python-tornado"
 	depends on BR2_PACKAGE_PYTHON
+	select BR2_PACKAGE_PYTHON_ZLIB
 	help
 	  Tornado is a Python web framework and asynchronous networking
 	  library, originally developed at FriendFeed.