Change output range for PackageVersionParser.versionMagnitude

It's now back to returning 10000 for "1.0.0", as it was before
the recent changes to allow for wrapped package version numbers
and prerelease versions. Given that there are other constants
in the cost function used in the constraint solver, this gives
us much more confidence that we haven't fundamentally changed
the behavior of `meteor add` or `meteor update` in 0.9.3.