Fix logging message template in AlluxioMasterProcess

[dbw9580]

The logging message template in AlluxioMasterProcess should use {} as a placeholder, instead of %s.

Change this line of code:

https://github.com/Alluxio/alluxio/blob/e0bd13efcf98c79ef7d7848a22a48fe0408c1680/core/server/master/src/main/java/alluxio/master/AlluxioMasterProcess.java#L194

    LOG.info("Starting all masters as: %s.", (isLeader) ? "leader" : "follower");

to

    LOG.info("Starting all masters as: {}.", (isLeader) ? "leader" : "follower");

[xwzbupt]

/assign @xwzbupt

[dbw9580]

Fixed by Alluxio/alluxio#14683