Removing specs from finagle/finagle-native test.

Going along with the corresponding issue https://github.com/twitter/finagle/issues/290 and my other PR on the subject https://github.com/twitter/finagle/pull/292


Just to make sure I'm reading this right you're saying to just run the code in Context, rather then newing up the class? Shouldn't the block in the class be ran upon instantiation?