userguide: Don't use pandoc for final tex output

When using pandoc to create the main .tex document, we lose all styles
and formatting information in the main userguide doc.

This change reverts commit bba5b1817e89bd63766e2bb91d406130f027fcaf, and
adds the \tighlist macro that was required by that change.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
diff --git a/Makefile b/Makefile
index 261867b..02ea525 100644
--- a/Makefile
+++ b/Makefile
@@ -6,12 +6,9 @@
 
 .PHONY: all clean
 
-userguide.pdf: userguide.tex
+userguide.pdf: userguide/userguide.tex
 	$(tex) $^
 
-userguide.tex: userguide/userguide.tex
-	pandoc -f latex -t latex -s -o $@ $^
-
 userguide/userguide.tex: rest-api.tex host-management.tex console.tex code-update.tex
 
 %.tex: %.md