curl rc file for connecting to external OpenSearch without auth enabled causes logstash startup to fail

[mmguero]

In malcolm_utils.py we have this:

###################################################################################################
# parse a curl-formatted config file, with special handling for user:password and URL
# see https://everything.curl.dev/cmdline/configfile
# e.g.:
#
# given .opensearch.primary.curlrc containing:
# -
# user: "sikari:changethis"
# insecure
# -
#
# ParseCurlFile('.opensearch.primary.curlrc') returns:
#   {
#    'user': 'sikari',
#    'password': 'changethis',
#    'insecure': ''
#   }
def ParseCurlFile(curlCfgFileName):
    result = defaultdict(lambda: None)
...

That first line needs to be changed to:

def ParseCurlFile(curlCfgFileName):
    result = defaultdict(lambda: '')
...

To avoid a startup error like this:

logstash_1            | 2023-06-14 14:56:22,791 INFO spawned: 'logstash' with pid 24089
logstash_1            | Traceback (most recent call last):
logstash_1            |   File "<string>", line 1, in <module>
logstash_1            | TypeError: unsupported operand type(s) for +: 'NoneType' and 'str'

However I'm still not 100% sure this will fix the problem, need to repro locally. Reported by user Carlos Lopez in slack.