This package is depending on dev-python/mysql-python which is broken and abandoned by upstream. You should attempt to switch to dev-python/mysqlclient which is a continued fork of mysql-python. Please test that it works like it's supposed to, so broken mysql-python can be last-rited and removed from the tree.
Here's the dependency expression in the netdata ebuild: mysql? ( || ( dev-python/mysqlclient[${PYTHON_USEDEP}] dev-python/mysql-python[${PYTHON_USEDEP}] ) ) dev-python/mysqlclient will be preferred, but dev-python/mysql-python is also acceptable. I think that this implementation addresses your concern. If/when dev-python/mysql-python is removed from the Gentoo tree, this dependency can be trivially removed from the netdata ebuilds.
Yes, that's good. Never trust automation... I'll add a note for myself to remove the condition while removing mysql-python. Thanks!