sys-apps/portage: version bump to 2.3.11

sys-apps/portage: version bump to 2.3.11

Fixed bugs:

  #631820 - postinst-qa-check.d/50xdg-utils unconditionally calls binaries
            it doesn't depend on and gets confused
  #631894 - depgraph _minimize_children method randomly chooses packages
            to eliminate
  #632202 - slot conflict solver interferes with @preserved-rebuild
  #632210 - SlotConflictUpdateTestCase fails with @world
  #632598 - --autounmask USE changes can trigger unnecessary backtracking
  #632696 - Files found by xdg_desktop_database_check() leak to
            xdg_mimeinfo_database_check()

Package-Manager: Portage-2.3.11, Repoman-2.3.3