debian: make sure ndmp headers are generated first

Due to broken ordering in the makefile the ndmp headers might be created
too late. This patch now generates them before invoking the "real" make.

debian/rules

@@ -99,6 +99,10 @@ override_dh_auto_configure:
 		dh_auto_configure -- $(CONFIGURE_FULL); \
 	fi
 
+override_dh_auto_build:
+	make -C src/ndmp ndmp0.h ndmp2.h ndmp3.h ndmp4.h ndmp9.h
+	dh_auto_build
+
 override_dh_fixperms:
 	# all files in /etc/bareos
 	dh_fixperms \