Galera suite MTR tests issuing wsrep_recover fail

MTR tests which start mysqld with --wsrep_recover, through wsrep_recover.inc, fail systematically. The problem is in error log redirection, test suite expects to find error log for recovery phase to be found in tmp/galera_wsrep_recover.log file, but with current test suite, that does not happen.

Vulnerable tests are:

• galera_gcache_recover_full_gcache
• galera_gcache_recover_manytrx
• galera_gcache_recover
• galera_ist_restart_joiner
• mysql-wsrep#31

The problem is present at least in 10.2 branch