Always parse region name the same way (with the same method)
Always parse region name the same way (with the same method)

Config#__get_region_option() had its own implementation of choosing a region,
which conflicted with Config#get_region_name(), so we dump it and use
get_region_name() in both cases.

Resolves https://github.com/SUSE/azurectl/issues/160

SUSE/azurectl,SUSE/azurectl,SUSE/azurectl