fix build of usermanual

Change-Id: Ibbe52ee595d13292ac2f2ef2b3477263894ed75c
diff --git a/doc/manuals/Makefile.am b/doc/manuals/Makefile.am
index 5aa75fe..1072ab5 100644
--- a/doc/manuals/Makefile.am
+++ b/doc/manuals/Makefile.am
@@ -9,7 +9,7 @@
 if BUILD_MANUALS
   ASCIIDOC = osmosmlc-usermanual.adoc
   include $(OSMO_GSM_MANUALS_DIR)/build/Makefile.asciidoc.inc
-  osmosmlc-usermanual.pdf: $(srcdir)/chapters/*.adoc $(srcdir)/chapters/*.dot
+  osmosmlc-usermanual.pdf: $(srcdir)/chapters/*.adoc #$(srcdir)/chapters/*.dot
 
   VTY_REFERENCE = osmosmlc-vty-reference.xml