use rspec double() instead of deprecated mock()

Author: alexch

spec/markdown_spec.rb

@@ -26,7 +26,7 @@
     )
 
     # this is a hack to make the TOC work in the absence of a real site
-    Site.should_receive(:named).and_return(mock(dir: "/tmp"))
+    Site.should_receive(:named).and_return(double(dir: "/tmp"))
 
     html_doc = Nokogiri.parse(page.to_html)
     main_html = html_doc.css("main").first.serialize(:save_with => 0).chomp

spec/step_page_spec.rb

@@ -18,7 +18,7 @@
     )
 
     # this is a hack to make the TOC work in the absence of a real site
-    Site.should_receive(:named).and_return(mock(dir: "/tmp"))
+    Site.should_receive(:named).and_return(double(dir: "/tmp"))
 
     html_doc = Nokogiri.parse(page.to_html)
     main_html = html_doc.css("main").first.serialize(:save_with => 0).chomp