Removed support for CSS such as "|X"

This expression could be used to get all elements that _don't_ have any
namespace. The problem is that this can't be expressed as just a node test,
instead the resulting XPath would have to look something like the following:

    X[local-name() = name()]

However, since the XPath predicates are already created for pseudo classes and
such, also injecting the above into it would be a real big pain. As such I've
decided not to support it.

lib/oga/css/parser.y

@@ -109,9 +109,6 @@ rule
 
     # ns|foo
     | T_IDENT T_PIPE T_IDENT { [val[0], val[2]] }
-
-    # |foo
-    | T_PIPE T_IDENT { [nil, val[1]] }
     ;
 
   predicates

spec/oga/css/evaluator/paths_spec.rb

@@ -108,20 +108,4 @@ describe 'CSS selector evaluation' do
       @set[2].should == @document.children[0].children[2]
     end
   end
-
-  context 'paths without namespaces and with name wildcards' do
-    before do
-      @set = evaluate_css(@document, 'a |*')
-    end
-
-    it_behaves_like :node_set, :length => 2
-
-    example 'include the first <b> node' do
-      @set[0].should == @document.children[0].children[0]
-    end
-
-    example 'include the second <b> node' do
-      @set[1].should == @document.children[0].children[1]
-    end
-  end
 end