Due to too many conflicts, I have dropped support for EAPI=prefix sooner

Due to too many conflicts, I have dropped support for EAPI=prefix sooner
than originally planned.  This commit removes the bits from ebuild.sh.

   Merged from trunk -r13296:13305

   | 13297   | Make emerge --info display USE similarly to how they are     |
   | zmedico | displayed in the merge list.                                 |

   | 13298   | Make RecursiveFileLoader skip hidden directories, and only   |
   | zmedico | use a single stat call to check for existence and file type. |

   | 13299   | Move the ebuild sourcing code into a new _source_ebuild()    |
   | zmedico | function.                                                    |

   | 13300   | - Move DEFINED_PHASES code into _source_ebuild() and add it  |
   | zmedico | to the list of readonly variables. - Save DEFINED_PHASES in  |
   |         | the vdb entries, as requested by lxnay.                      |

   | 13301   | Call _ebuild_phase_funcs() from ebuild_main() since it needs |
   | zmedico | to be called for every phase (for EAPI 2 default() phase     |
   |         | function setup).                                             |

   | 13302   | Bug #265111 - Make current options override older options    |
   | zmedico | for --resume.                                                |

   | 13303   | Add UseFlagDisplay.sort_combined and sort_separated          |
   | zmedico | attributes that can be passed directly as key parameters to  |
   |         | list.sort().                                                 |

   | 13304   | Reorganize emerge --info display, and make sure that the     |
   | zmedico | "cpv was built with the following" line is shown for every   |
   |         | package.                                                     |

   | 13305   | Don't try to execut the pkg_info phase if DEFINED_PHASES is  |
   | zmedico | available and it shows that the phase is undefined.          |

svn path=/main/branches/prefix/; revision=13320