sys-apps/portage: Bump to version 2.3.79

sys-apps/portage: Bump to version 2.3.79

 #673400 emerge: fix error message for unknown options
 #699392 emirrordist: _recycle_copier_exit UnboundLocalError
 #699400 emirrordist: clean up FileCopier exception logging
 #699548 install.py: ignore -Z / --context

Bug: https://bugs.gentoo.org/697734
Bug: https://bugs.gentoo.org/673400
Bug: https://bugs.gentoo.org/699392
Bug: https://bugs.gentoo.org/699400
Bug: https://bugs.gentoo.org/699548
Package-Manager: Portage-2.3.78, Repoman-2.3.17
Signed-off-by: Zac Medico <zmedico@gentoo.org>