Re-add spans to bsp @spans using splat operator

[plantfansam]

When we requeue spans for export after a timeout, we can inadvertently create a nested array in @spans. I believe that this behavior is unintentional, but I could be wrong.

An IRB session that sorta explains what I mean:

irb(main):001:0> x = [1,2]
=> [1, 2]
irb(main):002:0> x.unshift(*[3,4])
=> [3, 4, 1, 2]
irb(main):003:0> x.unshift([5,6])
=> [[5, 6], 3, 4, 1, 2]