update tests to follow changes in rev. 341 (comma in DEBPYTHON_SUPPORTED)

tests/common.mk

 #!/usr/bin/make -f
 
 export DEBPYTHON_DEFAULT ?= $(shell sed -rne 's,^default-version = python(.*),\1,p' ../../debian/debian_defaults)
-export DEBPYTHON_SUPPORTED ?= $(shell sed -rne '/^supported-versions/{s/^supported-versions = (.*)/\1/g;s/python//g;s/,//g;p}' ../../debian/debian_defaults)
+export DEBPYTHON_SUPPORTED ?= $(shell sed -rne '/^supported-versions/{s/^supported-versions = (.*)/\1/g;s/python//g}' ../../debian/debian_defaults)
 
 all: run check