Merged from trunk -r11694:11699

   Merged from trunk -r11694:11699

   | 11695   | Bug #242304 - When a zero-byte distfile is detected inside   |
   | zmedico | fetch(), discard the digests and attempt to fetch the file   |
   |         | if possible. This code is triggered via digestgen() when     |
   |         | appropriate, so it fixes all digestgen() callers, including  |
   |         | repoman.                                                     |

   | 11696   | In fetch(), don't spawn pkg_nofetch unless PORTAGE_BUILDDIR  |
   | zmedico | exists since it will die anyway due to the code for bug      |
   |         | #239560 that's in ebuild.sh.                                 |

   | 11697   | In fetch(), make sure all references to digests for          |
   | zmedico | zero-byte distfile are always discarded.                     |

   | 11698   | Remove support for FEATURES=gpg since it's already disabled  |
   | zmedico | and broken anyway. Thanks to DJ Anderson for the suggestion. |

   | 11699   | Remove the unused portage.gpg module and                     |
   | zmedico | portage_gpg_update.sh script.                                |

svn path=/main/branches/prefix/; revision=11700