Use Record.getMessage to implement user formatting in log messages.

[davemulford]

When falling back to using record.msg as a string, let's instead use Record.getMessage() which returns a string that has has the user-formatting applied. This allows %-style formatting to work as shown below.

import logging
from splunk_hec_handler import SplunkHecHandler
logger = logging.getLogger('SplunkHecHandlerExample')
logger.setLevel(logging.INFO)

# If using self-signed certificate, set ssl_verify to False
# If using http, set proto to http
splunk_handler = SplunkHecHandler('splunkfw.domain.tld',
                    'EA33046C-6FEC-4DC0-AC66-4326E58B54C3',
                    port=8888, proto='https', ssl_verify=True,
                    source="HEC_example")
logger.addHandler(splunk_handler)

name = "scooby"
age = 10
logger.info("Name is %s and age is %d", name, age)