Missing a case statement in simconvoi.cc

[Phystam]

See L1235 and there's no statement for state==EMERGENCY_STOP.
I checked all cases and there's no error except for this.

[jamespetts]

Thank you for that - now fixed.

[freddyhayward]

This couldn't have been a more timely fix, as the introduction of time-interval signals on the bridgewater-brunel server had just now caused a crash in its absence.