pycentral detects python installed version from /usr/bin/python*.
During postinst of python-osso, for example, pycentral installs it for every detected python-version. But, if /usr/bin/python2.7 exists, python2.7-minimal should be installed and /usr/lib/python2.7 should be a symlink, so we can let pycentral do his job. Do you agree ?

@marmistrz, something strange has happened in your system, like reinstalled those packages when you had a non-optified version of python2.7.
Check if these files are managed py pycentral