Fix bad paths in gemspec

Looks like the 4.0.1 release was entirely busted due to commit fcefbd9.
Hadn't exposed this in manual tested on my local development machine or
remotely.

Signed-off-by: Wincent Colaiuta <win@wincent.com>
Bump version for 4.0.2 release

Signed-off-by: Wincent Colaiuta <win@wincent.com>
Update release notes for 4.0.2

Signed-off-by: Wincent Colaiuta <win@wincent.com>
Update Gemfile.lock to sync with 4.0.2 release

Signed-off-by: Wincent Colaiuta <win@wincent.com>
Bump version number post-release

Signed-off-by: Wincent Colaiuta <win@wincent.com>