Remove expectation

This text is no longer outputted because we pass in the quiet flag and
as of the commit linked below, we no longer use puts which previously
ignored that flag.

solidusio/solidus@0a0313a

Author: AlistairNorman

spec/features/create_extension_spec.rb

@@ -114,7 +114,6 @@ def check_bundle_install
   def check_default_task
     cd(install_path) do
       output = sh("bin/rake")
-      expect(output).to include("Generating dummy Rails application")
       expect(output).to include("0 examples, 0 failures")
     end
   end