More strict checking on required packages

Author: Hubert Plociniczak

Makefile

@@ -37,7 +37,7 @@ ensure-deliverables: rabbit-vsn
 	file ${RELEASE_DIR}/${NAME_VSN}-net-3.0-wcf-htmldoc
 
 ensure-prerequisites: rabbit-vsn
-	dpkg -p htmldoc plotutils transfig graphviz > /dev/null
+	dpkg -L htmldoc plotutils transfig graphviz > /dev/null
 
 ensure-release-dir: rabbit-vsn
 	touch ${RELEASE_DIR}/