DmesgPlugin update: skip dmesg.log

[alexandraBara]

Added collection_arg option to skip writing dmesg.log to disk.
How to run:

node-scraper run-plugins DmesgPlugin --log_dmesg_data false

or with plugin_config.py:

{
  "global_args": {},
  "plugins": {
    "DmesgPlugin": {
          "collection_args": {
            "log_dmesg_data": 0
          }
        }
  },
  "result_collators": {},
  "name": "plugin_config",
  "desc": "Auto generated config"
}

and run:

 node-scraper --plugin-configs ~/plugin_config_dmesg.plugin

[landrews-amd]

Think this should be changed to something like 'log_dmesg_data' instead