testing: Install python-daemon via Debian package

System-wide installation via pip isn't easily possible anymore on Debian
bookworm, so just use the Debian package for this (is available in old
releases as well).

testing/scripts/recipes/013_strongswan.mk

@@ -130,5 +130,3 @@ build: configure
 install: build
 	cd $(BUILDDIR) && make -j install && \
 		cd $(DIR)/src/libcharon/plugins/vici/python && python3 setup.py install
-	# for Python-based updown scripts
-	pip3 install python-daemon