Fixed the /blocklocker command not working anymore in recent builds of Spigot and forks, due to a change in how signs are saved.
In those builds, the /blocklocker command still changed the appearance of signs, but didn't update the hidden text (containing the UUIDs) anymore, so the command had no effect. The hidden text is now cross-checked with what's displayed on the sign, so all corrupted protection signs will be fixed automatically.