libboost-all-dev, libboost-mpi-dev, and others broken in v2.2.0 and boost PPAs

[YenTheFirst]

on ubuntu 12.04, the libboost-all-dev package provided by the mapnik PPAs is uninstallable.

steps to reproduce:

1. on ubuntu 12.04, apt-get update and apt-get upgrade.
2. sudo add-apt-repository ppa:mapnik/boost
3. apt-get update
4. try to install libboost-all-dev.

This produces a dependency conflict. examining the situation in aptitude:

libboost-all-dev depends on libboost-mpi-dev
libboost-mpi-dev is available as 1.48 from ubuntu, or 1.49 from PPA. apt-get wants to install 1.49 from PPA. it depends on libboost-mpi1.49-dev.
libboost-mpi1.49-dev is not available.