test_sample.rb delete break after first button.

Since we now have completed tasks in our samples, there are two buttons
that match our criteria to find the delete button. So we need to ensure
only the first one is clicked

server/web2py/applications/vidjil/tests/functional/test_sample.rb

@@ -118,6 +118,7 @@ class TestSample < BrowserTest
       del = c.i(:class => "icon-erase")
       if del.present?
         del.click
+        break
       end
     end