It could just as well be on either part of the gitian build, but to safely put it on the Qt side would require bumping the filename, and every gitian user rebuilding it.
v0.5.3.1 put it on the Bitcoin side, and this is easier to work with and keep safe, so I'm moving it.
The only practical change here is updating the gitian URIs to the stable repository.
Otherwise, it just enables merging bugfixes from 0.4.x into 0.5.x properly.
Conflicts:
contrib/Bitcoin.app/Contents/Info.plist
doc/README
doc/README_windows.txt
doc/release-process.txt
share/setup.nsi
src/bitcoinrpc.cpp
src/headers.h
src/makefile.unix
src/serialize.h
src/ui.cpp