Minor change to not change default behavior
Minor change to not change default behavior

This change defaults ssh_config_path to None and does an
extra check in ._return_config() to keep this.

shamanu4/netmiko,ktbyers/netmiko,isidroamv/netmiko,shsingh/netmiko,shsingh/netmiko,isidroamv/netmiko,fooelisa/netmiko,shamanu4/netmiko,rdezavalia/netmiko,ktbyers/netmiko,fooelisa/netmiko,rdezavalia/netmiko