generate version.py by hand in debian package

we have to do this because upstream doesn't write it when we fake it

debian/rules

@@ -13,6 +13,13 @@ export PYTEST_USENETWORK
 %:
 	dh $@  --with=python2,sphinxdoc --buildsystem=pybuild
 
+override_dh_auto_build:
+	echo "# coding: utf-8" > monkeysign/_version.py
+	echo "# file generated by debian package" >> monkeysign/_version.py
+	echo "# see https://github.com/pypa/setuptools_scm/issues/101" >> monkeysign/_version.py
+	echo "version = '$(shell dpkg-parsechangelog -S version)'" >> monkeysign/_version.py
+	dh_auto_build
+
 override_dh_auto_test:
         # override locale to make sure tests pass
 	LANG=C.UTF-8 dh_auto_test