cli/config: improve error when failing to parse config file

The format had a stray colon and space included. While fixing that, also
updating the error message to clarify the error happened while parsing
the file (not so much "loading" it).

Before:

    WARNING: Error loading config file: /root/.docker/config.json: : json: cannot unmarshal bool into Go struct field ConfigFile.features of type string

After:

    WARNING: Error parsing config file (/root/.docker/config.json): json: cannot unmarshal bool into Go struct field ConfigFile.features of type string

Signed-off-by: Sebastiaan van Stijn <[email protected]>

cli/config/config.go

@@ -143,7 +143,7 @@ func load(configDir string) (*configfile.ConfigFile, error) {
 	defer file.Close()
 	err = configFile.LoadFromReader(file)
 	if err != nil {
-		err = errors.Wrapf(err, "loading config file: %s: ", filename)
+		err = errors.Wrapf(err, "parsing config file (%s)", filename)
 	}
 	return configFile, err
 }