Fixes: #14653
I was originally calling the wrong API method and only some of the
values were being persisted to state. By changing the API method, we can
now get all of the values and therefore can detech manual drift
```
% make testacc TEST=./builtin/providers/aws TESTARGS='-run=TestAccAWSSSMMaintenanceWindow_'
==> Checking that code complies with gofmt requirements...
go generate $(go list ./... | grep -v /terraform/vendor/)
2017/05/19 16:56:27 Generated command/internal_plugin_list.go
TF_ACC=1 go test ./builtin/providers/aws -v -run=TestAccAWSSSMMaintenanceWindow_ -timeout 120m
=== RUN TestAccAWSSSMMaintenanceWindow_basic
--- PASS: TestAccAWSSSMMaintenanceWindow_basic (41.39s)
PASS
ok github.com/hashicorp/terraform/builtin/providers/aws 41.419s
```
* provider/aws: Add support for aws_ssm_maintenance_window
Fixes: #14027
```
% make testacc TEST=./builtin/providers/aws TESTARGS='-run=TestAccAWSSSMMaintenanceWindow_basic'
==> Checking that code complies with gofmt requirements...
go generate $(go list ./... | grep -v /terraform/vendor/)
2017/04/29 13:38:19 Generated command/internal_plugin_list.go
TF_ACC=1 go test ./builtin/providers/aws -v -run=TestAccAWSSSMMaintenanceWindow_basic -timeout 120m
=== RUN TestAccAWSSSMMaintenanceWindow_basic
--- PASS: TestAccAWSSSMMaintenanceWindow_basic (51.69s)
PASS
ok github.com/hashicorp/terraform/builtin/providers/aws 51.711s
```
* provider/aws: Add documentation for aws_ssm_maintenance_window
* provider/aws: Add support for aws_ssm_maintenance_window_target
```
% make testacc TEST=./builtin/providers/aws TESTARGS='-run=TestAccAWSSSMMaintenanceWindowTarget'
==> Checking that code complies with gofmt requirements...
go generate $(go list ./... | grep -v /terraform/vendor/)
2017/04/29 16:38:22 Generated command/internal_plugin_list.go
TF_ACC=1 go test ./builtin/providers/aws -v -run=TestAccAWSSSMMaintenanceWindowTarget -timeout 120m
=== RUN TestAccAWSSSMMaintenanceWindowTarget_basic
--- PASS: TestAccAWSSSMMaintenanceWindowTarget_basic (34.68s)
PASS
ok github.com/hashicorp/terraform/builtin/providers/aws 34.701s
```
* provider/aws: Adding the documentation for aws_ssm_maintenance_window_target
* provider/aws: Add support for aws_ssm_maintenance_window_task
* provider/aws: Documentation for aws_ssm_maintenance_window_task