Stop using deprecated oslo_concurrency and sql_connection config options

As per the logs:
 Option "lock_path" from group "DEFAULT" is deprecated. Use option "lock_path" from group
"oslo_concurrency".

Option "sql_connection" from group "DEFAULT" is deprecated. Use option
"connection" from group "database".

Change-Id: I2109cec07ebee916c9ce0ccd24bd9a47d8d3c688
diff --git a/lib/ironic b/lib/ironic
index bc30cdb..a65ea88 100644
--- a/lib/ironic
+++ b/lib/ironic
@@ -273,7 +273,7 @@
     cp $IRONIC_DIR/etc/ironic/ironic.conf.sample $IRONIC_CONF_FILE
     iniset $IRONIC_CONF_FILE DEFAULT debug True
     inicomment $IRONIC_CONF_FILE DEFAULT log_file
-    iniset $IRONIC_CONF_FILE DEFAULT sql_connection `database_connection_url ironic`
+    iniset $IRONIC_CONF_FILE database connection `database_connection_url ironic`
     iniset $IRONIC_CONF_FILE DEFAULT state_path $IRONIC_STATE_PATH
     iniset $IRONIC_CONF_FILE DEFAULT use_syslog $SYSLOG
     # Configure Ironic conductor, if it was enabled.