Problem:
Load_log_event::print_query() function does not put escape character in file name 
for "LOAD DATA INFILE" statement.

Analysis:
When we have "'" in our file name for "LOAD DATA INFILE" statement,
Load_log_event::print_query() function does not put escape character 
in our file name.

This one result that when we show binary-log, we get file name without 
escape character.

Solution:
To put escape character when we have "'" in file name, for this instead of using 
simple memcpy() to put file-name, we will use pretty_print_str().