Broker does not show enough debug info when config file has issues loading

[sgnn7]

Summary

When a config file is loaded, we show the same message for both errors in finding the file as well as loading the file.

Steps to Reproduce

Use this config file:

version: 2
services:
  tcp-connector:
    connector: pg
    credentials:
      password:
        from: env
        get: PG_PASSWORD

Expected Results

2019/12/31 17:23:03 Secretless v1.4.1-06d11d3 starting up...
2019/12/31 17:23:03 Initializing health check on :5335...
2019/12/31 17:23:03 Initialization of health check done. You can access the endpoint at `/live` and `/ready`.
2019/12/31 17:23:03 Trying to load ./secretless.yml...
2019/12/31 17:23:03 [FATAL] Configuration file ./secretless.yml could not be parsed!
<maybe add more error info here>

Actual Results (including error logs, if applicable)

2019/12/31 17:22:23 Secretless v1.4.1-06d11d3 starting up...                                                                                                                                                                                    
2019/12/31 17:22:23 Initializing health check on :5335...                                                     
2019/12/31 17:22:23 Initialization of health check done. You can access the endpoint at `/live` and `/ready`.                                                                                                                                               
2019/12/31 17:22:23 Trying to load ./secretless.yml...                                                        
2019/12/31 17:22:23 WARN: Could not load ./secretless.yml. Skipping...     

This log output is the same when the config file cannot be found.