`red carpet` won't install on jruby.
Fix spec that was failing on jruby.

On jruby, the error for calling an undefined method
is a bit inconsistent:

The first time:

"undefined method `abcd' for #<#<Class:0x3cdb8522>:0x70019a64>"

The second time:

"undefined local variable or method `abcd' for #<#<Class:0x3cdb8522>:0x70019a64>"
Merge pull request #499 from rspec/fix-jruby-builds

Fix jruby builds