* [updategraph] add support to use preset config instead of default minigraph * Fix variable case * Remove default minigraph case * Remove default minigraphs and add default_sku files
* Move platform-specific ONIE installer config files with rest of device-specific files * Merge contents of dell-s6000-replace-reboot.sh into s6000 installer conf file * Remove dell-s6000-replace-reboot.sh