When parsing redis port, get last element after ':' instead of second

[casey-green]

The token parsed from netstat can take one of two forms: "0 0.0.0.0:6379" and ":::6379". If the for-loop hits the latter line first, then the line throws an exception. This modification ensures that both formats are supported.

I'm running this collector on Linux 3.2.30-49.59.amzn1.x86_64 EC2 box in AWS.

$ netstat --version
net-tools 1.60
netstat 1.42 (2001-04-15)

Here is an example output of the netstat command:

$ sudo netstat -tnlp
tcp        0      0 0.0.0.0:6379            0.0.0.0:*               LISTEN      7621/redis-server *
tcp6       0      0 :::6379                 :::*                    LISTEN      7621/redis-server *