Currently Heka fails to parse the RabbitMQ logs. There are two
problems:

1. The rabbit-sasl.log file is ignored but the file_match expression
   does not match.
2. The delimiter used in the RegexSplitter makes Heka stop on the
   very first log entry. '\n\n(=[^=]+====' (with two \n's) is
   a better delimiter. deliver_incomplete_final is used to get the
   final log entry.

TrivialFix

Change-Id: I94720340d5b2d6fd5d7641b9ff58733f6cd882ee