Remove unused param from OCC, add puzzle for test

src/main/java/org/jpeek/Report.java

@@ -205,6 +205,10 @@ public void save(final Path target) throws IOException {
      * Make XML.
      * @return XML
      * @throws IOException If fails
+     * @todo #326:30min Add a test to check whether passing params to
+     *  XSLDocument really works. Currently only C3 metric template
+     *  is known to use parameter named 'ctors'. However C3.xsl is a
+     *  work in progress and has impediments, see #175.
      */
     private XML xml() throws IOException {
         final String name = String.format("metrics/%s.xsl", this.metric);

src/main/resources/org/jpeek/metrics/OCC.xsl

@@ -23,7 +23,6 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 -->
 <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0">
-  <xsl:param name="ctors" select="0"/>
   <xsl:template match="skeleton">
     <metric>
       <xsl:apply-templates select="@*"/>