logging: example_logging: Add more testcases.

Author: pfalcon

logging/example_logging.py

@@ -4,3 +4,7 @@
 log = logging.getLogger("test")
 log.debug("Test message: %d(%s)", 100, "foobar")
 log.info("Test message2: %d(%s)", 100, "foobar")
+log.warning("Test message3: %d(%s)")
+log.error("Test message4")
+log.critical("Test message5")
+logging.info("Test message6")