percona-playback doesn't show an error if it can't connect

[Miguel Angel Nieto]

If the tool doesn't show an error when trying to connect it is really hard to debug it...

# percona-playback --input-plugin=tcpdump --db-plugin=libmysqlclient --mysql-host=WHATEVER_IT_DOESNT_CARE --mysql-username=WHATEVER --mysql-schema=WHATEVER --tcpdump-file=/root/example2.dump
Database Plugin: libmysqlclient
 Running...
Error Report finished

Detailed Report
----------------
SELECTs : 0 queries (0 faster, 0 slower)
INSERTs : 0 queries (0 faster, 0 slower)
UPDATEs : 0 queries (0 faster, 0 slower)
DELETEs : 0 queries (0 faster, 0 slower)
REPLACEs : 0 queries (0 faster, 0 slower)
DROPs : 0 queries (0 faster, 0 slower)

Report
------
Executed 0 queries
Spent 00:00:00 executing queries versus an expected 00:00:00 time.
0 queries were quicker than expected, 0 were slower
A total of 0 queries had errors.
Expected 0 rows, got 0 (a difference of 0)
Number of queries where number of rows differed: 0.

Average of -nan queries per connection (0 connections).