Merged from trunk 8315:8319

   Merged from trunk 8315:8319

   | 8316    | In portage.fetch(), condense digest check ouput to a single  |
   | zmedico | line for all digests.                                        |

   | 8317    | Fix broken $ROOT handling for setconfig in the MergeTask     |
   | zmedico | constructor.                                                 |

   | 8318    | Reuse an existing EmergeConfig instance instead of           |
   | zmedico | constructing a new one.                                      |

   | 8319    | Make depgraph._select_atoms() more flexible by allowing the  |
   | zmedico | repositories to be passed in as a parameter.                 |

svn path=/main/branches/prefix/; revision=8321