dim: Allow running without .dimrc
Since commit e700ea2f ("dim: Introduce a new configuration file in
.config/dim") it's not possible to run dim checkpatch
anymore without
a config file. Check for the existence of both $XDG_CONFIG_HOME/dim/dimrc
and $HOME/.dimrc before sourcing them.
Signed-off-by: Lucas De Marchi lucas.demarchi@intel.com