In mysqlbinlog, there was a problem with how we escaped the content of a string user variable.
To be perfect, we should have escaped with character_set_client. But this charset is unknown
to mysqlbinlog. So the simplest is to print the string in hex. This is unreadable but
100% safe with any charset (checked with Bar), no more need to bother with character_set_client.


mysql-test/r/rpl_charset.result:
  hex strings
mysql-test/r/rpl_user_variables.result:
  hex strings
mysql-test/r/user_var.result:
  hex strings
sql/log_event.cc:
  In mysqlbinlog, there was a problem with how we escaped the content of a string user variable.
  To be perfect, we should have escaped with character_set_client. But this charset is unknown
  to mysqlbinlog. So the simplest is to print the string in hex. This is unreadable but
  100% safe with any charset (checked with Bar), no more need to bother with character_set_client.