Actually check for 0.9.1...
Actually check for 0.9.1...

Fun fact: some packages of librdkafka 0.9.0, such as the one in the
Confluent Platform 2.0 Debian repo, define RD_KAFKA_VERSION as
0x00090100!

confluentinc/bottledwater-pg,confluentinc/bottledwater-pg,confluentinc/bottledwater-pg,confluentinc/bottledwater-pg