Initialize @location
Initialize @location

Fixes the following warning when run under -w:
  aws-sdk-core-3.16.0/lib/seahorse/model/shapes.rb:39:
    warning: instance variable @location not initialized

aws/aws-sdk-ruby,llooker/aws-sdk-ruby,llooker/aws-sdk-ruby,aws/aws-sdk-ruby,llooker/aws-sdk-ruby,aws/aws-sdk-ruby