Update ONOS version to 1.6.0-rc4

Change-Id: Icfef1d2751a3e0d229352a1b5007d8507ec9e247
diff --git a/pom.xml b/pom.xml
index fe8be1a..39cb210 100644
--- a/pom.xml
+++ b/pom.xml
@@ -22,7 +22,7 @@
     <parent>
         <groupId>org.onosproject</groupId>
         <artifactId>onos</artifactId>
-        <version>1.6.0-rc2</version>
+        <version>1.6.0-rc4</version>
         <relativePath></relativePath>
     </parent>
 
@@ -42,7 +42,7 @@
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <onos.version>1.6.0-rc2</onos.version>
+        <onos.version>1.6.0-rc4</onos.version>
         <onos.app.name>org.opencord.olt</onos.app.name>
         <onos.app.title>OLT Access Management</onos.app.title>
         <onos.app.origin>OpenCord</onos.app.origin>