Bumping pom versions to 1.7.0-rc2 and fixing some maven issues

Change-Id: I6169420328333d0916452aa92efbfa961d72e9c4
diff --git a/incubator/protobuf-nb/pom.xml b/incubator/protobuf-nb/pom.xml
index e4a3608..a6657d5 100644
--- a/incubator/protobuf-nb/pom.xml
+++ b/incubator/protobuf-nb/pom.xml
@@ -21,7 +21,7 @@
     <parent>
         <artifactId>onos-incubator</artifactId>
         <groupId>org.onosproject</groupId>
-        <version>1.7.0-SNAPSHOT</version>
+        <version>1.7.0-rc2</version>
     </parent>
     <modelVersion>4.0.0</modelVersion>