Add 'make clean' target, use it for Debian build

Since orig tarball exclude files from .gitignore, make sure make clean
remove them - otherwise dpkg-source complains.

.gitignore

@@ -3,3 +3,4 @@
 build/
 pkgs/
 .coverage
+__pycache__

Makefile

@@ -12,3 +12,9 @@ install:
 	$(PYTHON) setup.py install -O1 $(PYTHON_PREFIX_ARG) --root $(DESTDIR)
 	install -d $(DESTDIR)/etc/xdg/autostart
 	install -m 0644 etc/qvm-start-gui.desktop $(DESTDIR)/etc/xdg/autostart/
+
+clean:
+	rm -rf test-packages/__pycache__ qubesadmin/__pycache__
+	rm -rf qubesadmin/*/__pycache__ qubesadmin/tests/*/__pycache__
+	rm -rf test-packages/*.egg-info
+	rm -f .coverage

debian/rules

@@ -37,6 +37,10 @@ override_dh_auto_install:
 	install -m 0644 build/man/* \
 		debian/qubes-core-admin-client/usr/share/man/man1/
 
+override_dh_clean:
+	dh_clean -O--buildsystem=pybuild
+	make clean
+
 # debmake generated override targets
 # This is example for Cmake (See http://bugs.debian.org/641051 )
 #override_dh_auto_configure: