packethandler-model unable to parse yang sources

See: https://jenkins.opendaylight.org/releng/view/autorelease/job/autorelease-daily-beryllium/206/org.opendaylight.l2switch.packethandler$packethandler-model/console

There seems to be some yang parser issues with l2switch:

[ERROR] yang-to-sources: Unable to parse yang files from /w/workspace/autorelease-daily-beryllium/l2switch/packethandler/model/src/main/yang
org.opendaylight.yangtools.yang.parser.spi.meta.SomeModifiersUnresolvedException: Some of EFFECTIVE_MODEL modifiers for statements were not resolved.