sys-apps/portage: version bump to 2.3.23

sys-apps/portage: version bump to 2.3.23

  #646314 - fix "gpg: Can't check signature: No public key"

Bug: https://bugs.gentoo.org/646314
Package-Manager: Portage-2.3.23, Repoman-2.3.6

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# Date:      Thu Feb 1 15:33:14 2018 -0800
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# On branch master
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# Changes to be committed:
#	modified:   Manifest
#	renamed:    portage-2.3.22.ebuild -> portage-2.3.23.ebuild
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