Improve Heplify error messages for TCP connections

[Dletta]

Some error messages can be confusing or with little detail for example:

Sep 30 13:47:27 WGC-HEP-PXY-01 /usr/local/bin/heplify[22187]: sniffer.go:717: closed tcp connection [1]: EOF
Sep 30 13:46:29 WGC-HEP-PXY-02 /usr/local/bin/heplify[16282]: sniffer.go:717: closed tcp connection [1]: EOF

The errors should be more indicative to what this connection is for troubleshooting the cause of early socket termination.

For example, is it an incoming connection to heplify, or is it an outgoing connection from Heplify to Homer?

The error is thrown here for incoming connections:

heplify/sniffer/sniffer.go

Line 717 in 9d102bb

logp.Err("closed tcp connection [1]: %s", err.Error())

We should consider amending the error to something like below:

Sep 30 13:47:27 WGC-HEP-PXY-01 /usr/local/bin/heplify[22187]: sniffer.go:717: Incoming client closed tcp connection improperly [1]: EOF

[kYroL01]

Fixed by #305