bump(sys-apps/portage): sync with upstream
clean(portage-stable): Prune old ebuilds to fix Manifest files

Many updates from upstream have added files without pruning the old.
This leaves the Manifest file incomplete because it only includes the
new files that were copied with it. This causes errors when building a
distfiles mirror because the tool cannot validate those old files.

No need to keep these old ebuilds around so just delete them.
bump(net-misc/gsutil): sync with upstream

Get a version of gsutil with the cp -n "no-clobber" option

Packages updated:
  dev-python/boto
  net-misc/gsutil
Merge pull request #7 from marineam/fix-digests

Fix digests