software/slapos-testing: make python3 the default

software.cfg becomes python 3
software-py3.cfg no longer exists
software-py2.cfg is introduced

Test suites will have to be updated accordingly

software/slapos-testing/software-py3.cfg → software/slapos-testing/software-py2.cfg

@@ -3,4 +3,4 @@ extends =
   software.cfg
 
 [python]
-part = python3
+part = python2.7

software/slapos-testing/software.cfg

@@ -30,9 +30,6 @@ parts =
   phantomjs
   template
 
-[python]
-part = python2.7
-
 [bootstrap-slapos.recipe.cmmi]
 # install our develop version of slapos.recipe.cmmi before anything else,
 # otherwise it will be installed from pypi by dependencies.