Merged from trunk 8450:8453

   Merged from trunk 8450:8453

   | 8451    | Make depgraph.select_files() perform internal expansion of   |
   | zmedico | package set arguments since ideally the depgraph needs to be |
   |         | awary of the precise origin of each atom.                    |

   | 8452    | Fix broken logic for --update greedy slot atoms in           |
   | zmedico | depgraph.select_files().                                     |

   | 8453    | Really fix broken logic for --update greedy slot atoms in    |
   | zmedico | depgraph.select_files().                                     |

svn path=/main/branches/prefix/; revision=8454