Previously an attempt to destroy a LB stickiness policy would
result in an error like this:
```
* aws_lb_cookie_stickiness_policy.foo: Error removing LBCookieStickinessPolicy: LoadBalancerNotFound: There is no ACTIVE Load Balancer named 'tf-test-lb-tqatd'
status code: 400, request id: 28af1167-e4a4-11e6-8ddd-57ba410cbbb6
```
This checks for a missing load balancer on the policy read and allows
the destroy.
```
$ make testacc TEST=./builtin/providers/aws TESTARGS='-run=TestAccAWSLBCookieStickinessPolicy_missingLB'
==> Checking that code complies with gofmt requirements...
go generate $(go list ./... | grep -v /terraform/vendor/)
2017/01/27 07:21:11 Generated command/internal_plugin_list.go
TF_ACC=1 go test ./builtin/providers/aws -v -run=TestAccAWSLBCookieStickinessPolicy_missingLB -timeout 120m
=== RUN TestAccAWSLBCookieStickinessPolicy_missingLB
--- PASS: TestAccAWSLBCookieStickinessPolicy_missingLB (28.90s)
PASS
ok github.com/hashicorp/terraform/builtin/providers/aws 28.929s
```
If an AWS Cookie Stickiness Policy is removed from the listener in
the AWS console the policy isn't deleted. Cross reference the policy
name with those assigned to the listener to determine if the policy
is actually being used.
Jack Pearkes