Segfault Showing export table on 2.0.6

[Matt Corallo]

Sometimes showing export table(s) from birdc on 2.0.6 results in a
Segfault of the bird daemon. I can try to debug further if this isn't
sufficient, but largely the only difference between one protocol and the
other is the presence of communities on the exports from PROTO2.

birdc -s /root/bird-runtime/bird-3.ctl
BIRD 2.0.6 ready.
bird> show route export table PROTO1.ipv4 all
Table export:
69.59.18.0/24        unicast [v4sta 11:55:59.366] * (1000)
	dev lo
	Type: static univ
208.68.4.0/24        unicast [v4sta 11:55:59.366] * (1000)
	dev lo
	Type: static univ
bird> show route export table PROTO2.ipv4 all

...

2019-09-19 11:45:04.706302 bird-out-3.fifo Segmentation fault

Matt