distro-packages/python-rpm-macros: add more centos flavor
### flavor-specific: generate from flavor.in
+--- a/functions.lua 2017-12-07 11:46:04.000000000 -0800
++++ b/functions.lua 2017-12-08 09:44:39.000000000 -0800
+@@ -27,7 +27,7 @@
+ python = "py",
+ -- ??
+ python2 = "py2",
+- python3 = "py3",
++ python34 = "py3",
+ pypy = "pypy",
+ }
+
+--- a/macros/010-common-defs 2017-12-07 11:46:04.000000000 -0800
++++ b/macros/010-common-defs 2017-12-08 09:42:48.000000000 -0800
+@@ -1,5 +1,5 @@
+ %system_python python2
+-%python_for_executables python3
++%python_for_executables python34
+
+ ##### common functionality #####
+
