[skdb] Server "request tail" is broken

[beauby]

The "request tail" command of the SKDB replication protocol is currently broken. The call to skdb.canMirror() is missing a --data argument, but even then, it invokes skdb can-mirror <table_name> "<requested schema>", whereas <table_name> should be the actual schema of the table.

The reason this went unnoticed is probably that clients only use the "request tail batch" command, the implementation of which does not call canMirror.

Two possible fixes: ditch the canMirror() call in "request tail", or ditch the "request tail" command altogether, and only support "request tail batch".

[beauby]

Closing skdb-specific issues as skdb in its current form is being deprecated.