zyre: use a git snapshot that builds

Commit abe6a13c bumped the git snapshot for
zyre. Unfortunately, the newer snapshot requires a newer version of
czmq than is currently available in Buildroot. The simplest short-term fix is
to roll zyre back to an earlier git snapshot.

Fixes autobuild failures such as the following.

  http://autobuild.buildroot.net/results/0ef/0efbbcc7e94cdb184c5d032469e03b2b7da3d054/



Signed-off-by: Simon Dawson <spdawson@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>