docs-rst: Don't go to interactive mode on errors

When building for LaTeX, it stops and enters into interactive
mode on errors. Don't do that, as there are some non-fatal errors
on media books when using Sphinx 1.4.x that we don't know how fix
yet.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/Makefile.sphinx

@@ -72,7 +72,7 @@ ifeq ($(HAVE_PDFLATEX),0)
 	@echo "  SKIP    Sphinx $@ target."
 else # HAVE_PDFLATEX
 	@$(call loop_cmd,sphinx,latex,.,latex,.)
-	$(Q)$(MAKE) PDFLATEX=xelatex -C $(BUILDDIR)/latex
+	$(Q)$(MAKE) PDFLATEX=xelatex LATEXOPTS="-interaction=nonstopmode" -C $(BUILDDIR)/latex
 endif # HAVE_PDFLATEX
 
 epubdocs: