python-jsonschema: needs python-functools32 when used with python 2.7

>From setup.py:

extras_require = {
    ..
    ":python_version=='2.7'": ["functools32"],

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

package/python-jsonschema/Config.in

@@ -1,5 +1,6 @@
 config BR2_PACKAGE_PYTHON_JSONSCHEMA
 	bool "python-jsonschema"
+	select BR2_PACKAGE_PYTHON_FUNCTOOLS32 if BR2_PACKAGE_PYTHON # runtime
 	help
 	  An implementation of JSON Schema validation for Python.