Upgrade librdkafka to 0.11.1 to fix critical bug

[hrak]

librdkafka-0.11.1 was released recently to address a critical bug (Huge performance degradation (compared to v0.9.5) when fetching small batches.)

Please upgrade adisconhelperlrdk to this version

[friedl]

We try to stay up to date with this. The current packages already use librdkafka 0.10.0. We'll include this at latest with the next release.