Add allow_insecure and follow_redirects to load balancer monitor

[jacobbednarz]

This updates the cloudflare_load_balancer_monitor to accept two new
attributes:

• allow_insecure: Determine if the origin HTTPS certificate should be
  validated.
• follow_redirects: Should the monitor allow following a redirect if
  the origin presents it.

Fixes #113

[jacobbednarz]

Acceptance tests look good.

TF_ACC=1 go test -v github.com/terraform-providers/terraform-provider-cloudflare/cloudflare -run TestAccCloudflareLoadBalancerMonitor -timeout 120m
=== RUN   TestAccCloudflareLoadBalancerMonitor_Import
=== PAUSE TestAccCloudflareLoadBalancerMonitor_Import
=== RUN   TestAccCloudflareLoadBalancerMonitor_Basic
=== PAUSE TestAccCloudflareLoadBalancerMonitor_Basic
=== RUN   TestAccCloudflareLoadBalancerMonitor_FullySpecified
=== PAUSE TestAccCloudflareLoadBalancerMonitor_FullySpecified
=== RUN   TestAccCloudflareLoadBalancerMonitor_Update
=== PAUSE TestAccCloudflareLoadBalancerMonitor_Update
=== RUN   TestAccCloudflareLoadBalancerMonitor_CreateAfterManualDestroy
=== PAUSE TestAccCloudflareLoadBalancerMonitor_CreateAfterManualDestroy
=== CONT  TestAccCloudflareLoadBalancerMonitor_Import
=== CONT  TestAccCloudflareLoadBalancerMonitor_Basic
=== CONT  TestAccCloudflareLoadBalancerMonitor_Update
=== CONT  TestAccCloudflareLoadBalancerMonitor_FullySpecified
--- PASS: TestAccCloudflareLoadBalancerMonitor_Import (2.10s)
=== CONT  TestAccCloudflareLoadBalancerMonitor_CreateAfterManualDestroy
--- PASS: TestAccCloudflareLoadBalancerMonitor_FullySpecified (2.95s)
--- PASS: TestAccCloudflareLoadBalancerMonitor_Basic (3.72s)
--- PASS: TestAccCloudflareLoadBalancerMonitor_Update (5.81s)
--- PASS: TestAccCloudflareLoadBalancerMonitor_CreateAfterManualDestroy (4.94s)
PASS
ok  	github.com/terraform-providers/terraform-provider-cloudflare/cloudflare	7.064s

[scottrobertson]

Any movement on this?

[jacobbednarz]

@scottrobertson I've been waiting on confirmation from the issue raisers whether this has addressed their initial problem (see linked issue).

If I don't hear back soon, I'll merge anyway.