polygraph-ltrace cannot extract traces from server and client side logs at the same time

[Pavel Kazlenka]

Steps to reproduce:

Pre-requisite:
You have polygraph binary log files collected on client and server sides e.g. client.log and server.log

1. Run polygraph-ltrace --side all --objects time,ok_xact.count *.log
>warning: log(s) have info from client and server sides, and no specific side was specified; assuming `clt' side
last/server.log:warning: failed to read log file, skipping
> trace is not extracted from server.log
Expected: traces extracted from both server and client logs.

Workaround: extract traces from client and server sides separately.