Re-enable MiMa for Streaming Flume Sink module, now that 1.1.0 is released, per the JIRA TO-DO. That's pretty much all there is to this.

Author: Sean Owen <sowen@cloudera.com>

Closes #3842 from srowen/SPARK-2757 and squashes the following commits:

50ff80e [Sean Owen] Exclude apparent false positive turned up by re-enabling MiMa checks for Streaming Flume Sink
0e5ba5c [Sean Owen] Re-enable MiMa for Streaming Flume Sink module