Upgrade to Apache Karaf 4.2.8

Change-Id: I8ae525e6c8a04c0381c5e3bac39de1a7b85b4446
diff --git a/tools/build/build-offline-karaf b/tools/build/build-offline-karaf
index cdd245c..554f532 100755
--- a/tools/build/build-offline-karaf
+++ b/tools/build/build-offline-karaf
@@ -1,7 +1,7 @@
 #!/bin/bash
 
-KARAF_RELEASE_VERSION="4.2.6"
-KARAF_BASE_PACKAGE_VERSION="4.2.6"
+KARAF_RELEASE_VERSION="4.2.8"
+KARAF_BASE_PACKAGE_VERSION="4.2.8"
 KARAF_TARFILE_NAME="apache-karaf-${KARAF_RELEASE_VERSION}.tar"
 ADDED_BOOT_FEATURES="kar/${KARAF_RELEASE_VERSION},webconsole/${KARAF_RELEASE_VERSION},scr/${KARAF_RELEASE_VERSION},war/${KARAF_RELEASE_VERSION}"