Consolidate gRPC OSGi bundle handling

Change-Id: I01e5058e08372b142058769db081b8de154e1c9b
diff --git a/incubator/protobuf/features.xml b/incubator/protobuf/features.xml
index c19a13b..e8fbc06 100644
--- a/incubator/protobuf/features.xml
+++ b/incubator/protobuf/features.xml
@@ -18,7 +18,7 @@
     <feature name="${project.artifactId}" version="${project.version}"
              description="${project.description}">
         <feature>onos-api</feature>
-        <bundle>mvn:com.google.protobuf/protobuf-java/3.0.0</bundle>
+        <bundle>mvn:com.google.protobuf/protobuf-java/${protobuf.version}</bundle>
         <bundle>mvn:${project.groupId}/${project.artifactId}/${project.version}</bundle>
     </feature>
 </features>