[ONOS-8121][VOL-3259] Fixing null filter for felix fileinstall

Change-Id: Ib5ef99002ad1d0a40e767528223e324326f2c022
diff --git a/tools/package/onos-prep-karaf b/tools/package/onos-prep-karaf
index 50516c1..cd906dc 100755
--- a/tools/package/onos-prep-karaf
+++ b/tools/package/onos-prep-karaf
@@ -34,6 +34,10 @@
 perl -pi.old -e "s/maxFileSize=1MB/maxFileSize=10MB/g" \
     $KARAF_DIR/etc/org.ops4j.pax.logging.cfg
 
+# Patch the fileinstall to avoid NPE when filter is null
+echo "felix.fileinstall.filter=*.jar" >> \
+    $KARAF_DIR/etc/org.apache.felix.fileinstall-deploy.cfg
+
 # Patch-in proper Karaf version into the startup script
 perl -pi.bk -e 's/apache-karaf-\$KARAF_VERSION/$ENV{KARAF_DIR}/g' $SANDBOX/bin/onos-service