provider/aws: guard against aws_route53_record delete panic

Fixes #9025

We were assuming there would always be a changeInfo record and then
dereferencing the ID. This wasn't always the case (As noted in #9025)
where it was a delete rather than a delete / create action

```
% make testacc TEST=./builtin/providers/aws TESTARGS='-run=TestAccAWSRoute53Record_'
==> Checking that code complies with gofmt requirements...
go generate $(go list ./... | grep -v /terraform/vendor/)
2016/09/26 11:26:43 Generated command/internal_plugin_list.go
TF_ACC=1 go test ./builtin/providers/aws -v
-run=TestAccAWSRoute53Record_ -timeout 120m
=== RUN   TestAccAWSRoute53Record_basic
--- PASS: TestAccAWSRoute53Record_basic (114.99s)
=== RUN   TestAccAWSRoute53Record_basic_fqdn
--- PASS: TestAccAWSRoute53Record_basic_fqdn (126.64s)
=== RUN   TestAccAWSRoute53Record_txtSupport
--- PASS: TestAccAWSRoute53Record_txtSupport (113.25s)
=== RUN   TestAccAWSRoute53Record_spfSupport
--- PASS: TestAccAWSRoute53Record_spfSupport (112.89s)
=== RUN   TestAccAWSRoute53Record_generatesSuffix
--- PASS: TestAccAWSRoute53Record_generatesSuffix (113.29s)
=== RUN   TestAccAWSRoute53Record_wildcard
--- PASS: TestAccAWSRoute53Record_wildcard (163.05s)
=== RUN   TestAccAWSRoute53Record_failover
--- PASS: TestAccAWSRoute53Record_failover (121.15s)
=== RUN   TestAccAWSRoute53Record_weighted_basic
--- PASS: TestAccAWSRoute53Record_weighted_basic (117.06s)
=== RUN   TestAccAWSRoute53Record_alias
--- PASS: TestAccAWSRoute53Record_alias (116.97s)
=== RUN   TestAccAWSRoute53Record_s3_alias
--- PASS: TestAccAWSRoute53Record_s3_alias (138.79s)
=== RUN   TestAccAWSRoute53Record_weighted_alias
--- PASS: TestAccAWSRoute53Record_weighted_alias (241.48s)
=== RUN   TestAccAWSRoute53Record_geolocation_basic
--- PASS: TestAccAWSRoute53Record_geolocation_basic (132.51s)
=== RUN   TestAccAWSRoute53Record_latency_basic
--- PASS: TestAccAWSRoute53Record_latency_basic (121.29s)
=== RUN   TestAccAWSRoute53Record_TypeChange
--- PASS: TestAccAWSRoute53Record_TypeChange (189.31s)
=== RUN   TestAccAWSRoute53Record_empty
--- PASS: TestAccAWSRoute53Record_empty (127.31s)
PASS
ok      github.com/hashicorp/terraform/builtin/providers/aws
2050.012s
```

builtin/providers/aws/resource_aws_route53_record.go

@@ -534,6 +534,10 @@ func resourceAwsRoute53RecordDelete(d *schema.ResourceData, meta interface{}) er
 	}
 
 	changeInfo := respRaw.(*route53.ChangeResourceRecordSetsOutput).ChangeInfo
+	if changeInfo == nil {
+		log.Printf("[INFO] No ChangeInfo Found. Waiting for Sync not required")
+		return nil
+	}
 
 	err = waitForRoute53RecordSetToSync(conn, cleanChangeID(*changeInfo.Id))
 	if err != nil {