Update ONOS version to 1.6.0-rc4

Change-Id: I54cd2c09f6eedd032ff295b506886deafd9ae597
diff --git a/pom.xml b/pom.xml
index 2e923ad..ae21c81 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>
 
@@ -44,7 +44,7 @@
 
     <properties>
         <onos.app.name>org.opencord.igmp</onos.app.name>
-        <onos.version>1.6.0-rc2</onos.version>
+        <onos.version>1.6.0-rc4</onos.version>
         <onos.app.title>IGMP App</onos.app.title>
         <onos.app.category>Traffic Steering</onos.app.category>
         <onos.app.url>http://opencord.org</onos.app.url>