libv8-dev backport breaks some dependencies

There is no way to to install libv8-dev for version 3.7, as it's provided by the cloud archive and pointing to the 3.14 version. An alternative fix would be for 12.04 to provide a libv8-3.7-dev package. I think it makes sense to drop the libv8-dev from the cloud archive so it matches what is done with -dbg.

This is essential for having puppet-razor and mongodb on the same box.

$ apt-cache search libv8
libv8-3.7.12.22 - v8 JavaScript engine - runtime library
libv8-dbg - v8 JavaScript engine - debugging symbols (3.7)
libv8-3.14-dbg - V8 JavaScript engine - debugging symbols
libv8-3.14-dev - V8 JavaScript engine - development files for 3.14 branch
libv8-3.14.5 - V8 JavaScript engine - runtime library
libv8-dev - V8 JavaScript engine - development files for latest branch (3.14)

Steps to reproduce with a fresh 12.04 image:
sudo add-apt-repository cloud-archive:icehouse
sudo apt-get update
sudo apt-get install nodejs-dev
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 nodejs-dev : Depends: libv8-dev (< 3.8)
E: Unable to correct problems, you have held broken packages.