securityonion-bro-scripts: update sensortab.bro for Bro 2.4

[dougburks]

https://www.bro.org/download/NEWS.bro.html

"The split* family of functions are to be replaced with alternate versions that return a vector of strings rather than a table of strings. This also allows deprecation for some related string concatenation/extraction functions. Note that the new functions use 0-based indexing, rather than 1-based.
The full list of now deprecated functions is:
split: use split_string instead.
split1: use split_string1 instead.
split_all: use split_string_all instead.
"

[dougburks]

submitted for testing:
https://groups.google.com/d/topic/security-onion-testing/g7GxUYk5T3c/discussion

[dougburks]

updated sensortab.bro:
https://github.com/Security-Onion-Solutions/securityonion-bro-scripts/blob/master/sensortab.bro

[dougburks]

Published:
http://blog.securityonion.net/2015/08/bro-24-now-available-for-security-onion.html