Description
-----------
Running `rpl.rpl_multi_source_channel_map_stress` test script with `--valgrind`
option exposes a ` Conditional jump or move depends on uninitialised value(s)`.

Analysis
--------
Member variable `LOG_INFO::char log_file_name` is used as a parameter of
`dirname_length(char const*)`, where the valgrind memory error is caught.

Although a `memset` with `0` value is performed in the `LOG_INFO` struct
constructor, this is not a semantic-bound initialization and, therefore,
Valgrind is unable to include it has such.

Fix
---
Add ` = {0}` to the member variable declaration.

Reviewed-by: Pedro Gomes <pedro.gomes@oracle.com>