Changed command test for #2994 so it actually tests the writer.

pandoc.cabal

@@ -138,7 +138,6 @@ Extra-Source-Files:
                  test/*.native
                  test/command/*.md
                  test/command/3533-rst-csv-tables.csv
-                 test/command/2994.docx
                  test/command/abbrevs
                  test/command/SVG_logo-without-xml-declaration.svg
                  test/command/SVG_logo.svg

test/command/2994.md

@@ -1,5 +1,8 @@
 ```
-% pandoc --track-changes=all -t markdown command/2994.docx
+% pandoc -f markdown -t docx | pandoc -f docx -t markdown --track-changes=all
+I want [I left a comment.]{.comment-start id="0"
+author="Jesse Rosenthal" date="2016-05-09T16:13:00Z"}some text to have a
+comment []{.comment-end id="0"}on it.
 ^D
 I want [I left a comment.]{.comment-start id="0"
 author="Jesse Rosenthal" date="2016-05-09T16:13:00Z"}some text to have a