For some reason the test authentication plugin accepted connection with arbitrary password. But the intention of the plugin is that password should equal to the authentication string and in the later versions of the server connection fails if password is wrong. So I have updated auth_rpl test to specify the correct password.
Connection of slave to master using a replication account which authenticates
with an external plugin was not possible.
Fixed by making sure that the CLIENT_PLUGIN_AUTH capability is set when client connects using mysql_real_connect(). Also, a plugin-dir path used by client library to locate authentication plugins is set based on the analogous server setting. This is done in connect_to_master() function before a call to mysql_real_connect().
