add missing bindeps for docs

This add two more bindep targets to encode the
doc and pdf-docs deps.

Change-Id: Ide54be172c485025e567ede39c238b39b01c89e0

bindep.txt

@@ -12,3 +12,12 @@ python3-all-dev [platform:dpkg test]
 python3 [platform:rpm test]
 python3-devel [platform:rpm test]
 sqlite-devel [platform:rpm test]
+# gettext and graphviz are needed by doc builds only.
+gettext [doc]
+graphviz [doc]
+# fonts-freefont-otf is needed for pdf docs builds with the 'xelatex' engine
+fonts-freefont-otf [pdf-docs]
+texlive [pdf-docs]
+texlive-latex-recommended [pdf-docs]
+texlive-xetex [pdf-docs]
+latexmk [pdf-docs]