Tests: Unset pandoc-version so we don't get the comment...

in the man writer test.  Otherwise this needs updating
every version bump.

tests/Tests/Old.hs

@@ -196,7 +196,8 @@ writerTests format
     , test "tables" opts             "tables.native"    ("tables" <.> format)
     ]
   where
-    opts = ["-r", "native", "-w", format, "--columns=78"]
+    opts = ["-r", "native", "-w", format, "--columns=78",
+            "--variable", "pandoc-version="]
 
 s5WriterTest :: String -> [String] -> String -> Test
 s5WriterTest modifier opts format

tests/writer.man

@@ -1,5 +1,3 @@
-.\" Automatically generated by Pandoc 1.15.1
-.\"
 .hy
 .TH "Pandoc Test Suite" "" "July 17, 2006" "" ""
 .PP