pin to rack ~> 1.1 instead of ~> 1.1.0

Some pretty gnarly bugs and security issues are present in the
latest rack 1.1.x release. There are 1.2.x and 1.3.x releases that
correct these.

This changes the gem dependencies to allow for rack versions > 1.1.
At GitHub we're on 1.2.4 (latest 1.2.x release at present) and
should have some results from real world testing soon.

Conflicts:
	actionpack/Rakefile
the move to unpin rack from 1.1.0 to just 1.1 also needed to update the pregenerated gemspec