synctable: also require @_value_server to be defined when handling updates.
synctable: also require @_value_server to be defined when handling updates.

sagemathinc/smc,DrXyzzy/smc,sagemathinc/smc,tscholl2/smc,tscholl2/smc,sagemathinc/smc,tscholl2/smc,DrXyzzy/smc,tscholl2/smc,tscholl2/smc,sagemathinc/smc,DrXyzzy/smc,DrXyzzy/smc