HTML writer: harmless code simplification.

Since the 'math' is only put into the template if stMath is
set anyway, there's no need for this conditional.

src/Text/Pandoc/Writers/HTML.hs

@@ -140,8 +140,7 @@ pandocToHtml opts (Pandoc meta blocks) = do
   st <- get
   let notes = reverse (stNotes st)
   let thebody = blocks' >> footnoteSection opts notes
-  let  math = if stMath st
-                then case writerHTMLMathMethod opts of
+  let  math = case writerHTMLMathMethod opts of
                       LaTeXMathML (Just url) ->
                          H.script ! A.src (toValue url)
                                   ! A.type_ "text/javascript"
@@ -173,7 +172,6 @@ pandocToHtml opts (Pandoc meta blocks) = do
                                        ("/*<![CDATA[*/\n" ++ s ++ "/*]]>*/\n")
                                         | otherwise -> mempty
                                  Nothing -> mempty
-                else mempty
   let context =   (if stHighlighting st
                       then defField "highlighting-css"
                              (styleToCss $ writerHighlightStyle opts)