Changed error when loading without tracelycer installed after upgrade

Hi! I'm getting rails error traces instead of the used missing tracelytics libraries message. just after upgrading from oboe (2.4.0.1) to oboe (2.7.0.3)

Using:
ruby: ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-linux]
rake: rake 10.3.2

Steps to reproce:

In a clean system without tracelitycs installed

* Start a blank rails project
* Edit Gemfile adding 

```
gem 'oboe', '= 2.4.0.1'
```

* run `bundle`
* run `rake -T` to get:
```
==============================================================
Missing TraceView libraries.  Tracing disabled.
See: https://support.tv.appneta.com/solution/articles/137973
==============================================================
rake about                              # List versions of all Rails frameworks and the environment
...
```
* Edit Gemfile removing version constraint
```
gem 'oboe'
```
* `gem uninstall oboe`
* `rm Gemfile.lock`
* run `bundle` to update oboe to 2.7.0.3 (today)
* run rake -T to get

```
[oboe/error] Problem loading: #<NoMethodError: undefined method `loaded=' for Oboe:Module>
/home/carlos/.rbenv/versions/2.1.2/gemsets/oboe-ruby/gems/oboe-2.7.0.3/lib/oboe.rb:22:in `rescue in <top (required)>'
/home/carlos/.rbenv/versions/2.1.2/gemsets/oboe-ruby/gems/oboe-2.7.0.3/lib/oboe.rb:13:in `<top (required)>'
/home/carlos/.rbenv/versions/2.1.2/gemsets/oboe-ruby/gems/bundler-1.7.1/lib/bundler/runtime.rb:76:in `require'
/home/carlos/.rbenv/versions/2.1.2/gemsets/oboe-ruby/gems/bundler-1.7.1/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
/home/carlos/.rbenv/versions/2.1.2/gemsets/oboe-ruby/gems/bundler-1.7.1/lib/bundler/runtime.rb:72:in `each'
/home/carlos/.rbenv/versions/2.1.2/gemsets/oboe-ruby/gems/bundler-1.7.1/lib/bundler/runtime.rb:72:in `block in require'
/home/carlos/.rbenv/versions/2.1.2/gemsets/oboe-ruby/gems/bundler-1.7.1/lib/bundler/runtime.rb:61:in `each'
/home/carlos/.rbenv/versions/2.1.2/gemsets/oboe-ruby/gems/bundler-1.7.1/lib/bundler/runtime.rb:61:in `require'
/home/carlos/.rbenv/versions/2.1.2/gemsets/oboe-ruby/gems/bundler-1.7.1/lib/bundler.rb:133:in `require'
/home/carlos/repos/oss/oboe-ruby/TEST/foo/config/application.rb:7:in `<top (required)>'
/home/carlos/.rbenv/versions/2.1.2/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
/home/carlos/.rbenv/versions/2.1.2/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
/home/carlos/repos/oss/oboe-ruby/TEST/foo/Rakefile:4:in `<top (required)>'
/home/carlos/.rbenv/versions/2.1.2/gemsets/oboe-ruby/gems/rake-10.3.2/lib/rake/rake_module.rb:28:in `load'
/home/carlos/.rbenv/versions/2.1.2/gemsets/oboe-ruby/gems/rake-10.3.2/lib/rake/rake_module.rb:28:in `load_rakefile'

```


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