provider/aws: Fix refresh/plan issue with DB Param. Group name
provider/aws: Fix refresh/plan issue with DB Param. Group name

Check against AWS with lowercase, but store in state unmodified.

ashinohara/terraform-provider-aws,Ninir/terraform-provider-aws,ClementCunin/terraform-provider-aws,charles-at-geospock/terraform-provider-aws,terraform-providers/terraform-provider-aws,ashinohara/terraform-provider-aws,terraform-providers/terraform-provider-aws,charles-at-geospock/terraform-provider-aws,terraform-providers/terraform-provider-aws,ashinohara/terraform-provider-aws,charles-at-geospock/terraform-provider-aws,nbaztec/terraform-provider-aws,Ninir/terraform-provider-aws,charles-at-geospock/terraform-provider-aws,ashinohara/terraform-provider-aws,nbaztec/terraform-provider-aws,ClementCunin/terraform-provider-aws,Ninir/terraform-provider-aws,kjmkznr/terraform-provider-aws,terraform-providers/terraform-provider-aws,nbaztec/terraform-provider-aws,Ninir/terraform-provider-aws,nbaztec/terraform-provider-aws,ClementCunin/terraform-provider-aws,kjmkznr/terraform-provider-aws,ClementCunin/terraform-provider-aws,kjmkznr/terraform-provider-aws,kjmkznr/terraform-provider-aws