download karaf 4.2.1 from maven central

Change-Id: Icb7e0400ee5b34ed4be33afdda5074a6f6ec1f6d
diff --git a/tools/build/build-offline-karaf b/tools/build/build-offline-karaf
index f7f4a63..baaec33 100755
--- a/tools/build/build-offline-karaf
+++ b/tools/build/build-offline-karaf
@@ -1,6 +1,6 @@
 #!/bin/bash
-
-KARAF_VERSION="3.0.8"
+ 
+KARAF_VERSION="4.2.1"
 KARAF_TARFILE_NAME="apache-karaf-${KARAF_VERSION}.tar"
 BOOT_FEATURES="standard,ssh,scr,war,webconsole"