ola: mark as broken

ola: mark as broken

Build with current protobuf is broken. Mark as broken until upstream resolves
this issue.

https://github.com/OpenLightingProject/ola/issues/1192

Fixes:
http://autobuild.buildroot.net/results/d9a/d9a24f7b715100be1580a568a5e3ff72b0389165/
http://autobuild.buildroot.net/results/b31/b314811dedce04ebdc779df67de6cb59a1880cac/
http://autobuild.buildroot.net/results/587/5877b2301b7da43c50127a4c5f648acd3b0264cc/

Cc: Dave Skok <blanco.ether@gmail.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>