MOVED: do not specify a flavor when not necessary

in particular in case of python the flavors may get removed quickly
resulting in the linter yelling (rightfully)

MOVED

@@ -14905,7 +14905,7 @@ net-p2p/parity-ethereum|net-p2p/openethereum|2020-05-13|Renamed upstream for tra
 net-im/linux-telegram-desktop|net-im/telegram-desktop|2020-05-13|Has expired: Broken for more than 6 months, use native version
 devel/libphutil||2020-05-15|Has expired: Upstream merged functionality into downstream projects
 print/frescobaldi|print/py-frescobaldi|2020-05-16|Renamed to comply with Python Ports Policy
-sysutils/rdiff-backup|sysutils/py-rdiff-backup@py37|2020-05-16|Renamed comply with Python Ports Policy and flavored
+sysutils/rdiff-backup|sysutils/py-rdiff-backup|2020-05-16|Renamed comply with Python Ports Policy and flavored
 www/py-django-happenings|www/py-django-happenings-update|2020-05-17|Has expired: Doesn't work with Django 2.2+, please use www/py-django-happenings-update instead
 devel/py-django-tastypie-mongoengine||2020-05-17|Has expired: Not necessary anymore, and project unmaintained
 sysutils/py-cpuinfo|sysutils/py-py-cpuinfo|2020-05-18|Rename to match PyPI name