Bump karaf from 3.0.5 to 3.0.8

Change-Id: Ic5bc130f5110f4ff9da6ec22d066a5dd3069288d
diff --git a/bucklets/onos_app.bucklet b/bucklets/onos_app.bucklet
index 6771c0b..64dd9d7 100644
--- a/bucklets/onos_app.bucklet
+++ b/bucklets/onos_app.bucklet
@@ -64,7 +64,7 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
 <features xmlns="http://karaf.apache.org/xmlns/features/v1.2.0"
           name="onos-%s">
-    <repository>mvn:org.apache.karaf.features/standard/3.0.5/xml/features</repository>
+    <repository>mvn:org.apache.karaf.features/standard/3.0.8/xml/features</repository>
 
 ''' % ONOS_VERSION