Bug 1740: add missing features/mdsal/pom.xml dependencies

Bug 1740: add missing features/mdsal/pom.xml dependencies

features/mdsal/pom.xml lacks dependencies for the configfiles:

<configfile finalname="configuration/initial/akka.conf">mvn:org.opendaylight.controller/sal-clustering-config/${project.version}/xml/akkaconf</configfile>

<configfile finalname="configuration/initial/module-shards.conf">mvn:org.opendaylight.controller/sal-clustering-config/${project.version}/xml/moduleshardconf</configfile>

<configfile finalname="configuration/initial/modules.conf">mvn:org.opendaylight.controller/sal-clustering-config/${project.version}/xml/moduleconf</configfile>

This patch adds the necessary maven dependencies.

Change-Id: I6e28d4ad8650278fc207f0fb0a22afa4c2ce4bde
Signed-off-by: Ed Warnicke <eaw@cisco.com>