config: don't create default config dir when user supplies --config
config: don't create default config dir when user supplies --config

Avoid creating empty default configuration directory when user supplies path to config file.

Fixes #2514.
olihey/rclone,ncw/rclone,olihey/rclone,B4dM4n/rclone,ncw/rclone,olihey/rclone,B4dM4n/rclone,B4dM4n/rclone,ncw/rclone,olihey/rclone,B4dM4n/rclone,ncw/rclone