Fixes: #10958
This wasn't implemented the first time around for some reason
```
% make testacc TEST=./builtin/providers/aws TESTARGS='-run=TestAccAWSEMRCluster_' 2 ↵ ✹ ✭
==> Checking that code complies with gofmt requirements...
go generate $(go list ./... | grep -v /terraform/vendor/)
2017/01/03 15:40:09 Generated command/internal_plugin_list.go
TF_ACC=1 go test ./builtin/providers/aws -v -run=TestAccAWSEMRCluster_ -timeout 120m
=== RUN TestAccAWSEMRCluster_basic
--- PASS: TestAccAWSEMRCluster_basic (529.36s)
=== RUN TestAccAWSEMRCluster_tags
--- PASS: TestAccAWSEMRCluster_tags (556.81s)
PASS
ok github.com/hashicorp/terraform/builtin/providers/aws 1086.197s
```
cb64fdeb28