Bug#1028638: libproxy1v5: Gajim 1.6.0-1 crashes in libproxy call

[Martin]

Control: found -1 0.4.16-1
Control: notfound -1 0.4.15-15

I tried various versions of libproxy from snapshot.debian.org and could
find the crash to be introduced by version 0.4.16-1 exactly.