r/pagerduty_schedule: Add support for overflow

[heimweh]

This PR adds support for passing overflow when creating/updating schedules.

This PR also fixes a bug when creating/updating schedules (related to rotation_virtual_start).

The issue here is that if a user specifies a rotation_virtual_start time to be:
2017-09-01T10:00:00+02:00 the API returns back:
2017-09-01T12:00:00+02:00.

With this fix in place, we get the correct rotation_virtual_start time, thus eliminating diff issues we've been seeing in the past. This has been confirmed working by PagerDuty support.

Fixes: #21

[heimweh]

Tests are passing:

$ make testacc TEST=./pagerduty
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./pagerduty -v  -timeout 120m
=== RUN   TestConfigEmptyToken
--- PASS: TestConfigEmptyToken (0.00s)
=== RUN   TestConfigSkipCredsValidation
2017/08/10 00:09:05 [INFO] PagerDuty client configured
--- PASS: TestConfigSkipCredsValidation (0.00s)
=== RUN   TestAccDataSourcePagerDutyEscalationPolicy_Basic
=== RUN   TestAccDataSourcePagerDutySchedule_Basic
=== RUN   TestAccDataSourcePagerDutyUser_Basic
=== RUN   TestAccDataSourcePagerDutyVendor_Basic
=== RUN   TestAccPagerDutyEscalationPolicy_import
=== RUN   TestAccPagerDutyMaintenanceWindow_import
=== RUN   TestAccPagerDutySchedule_import
=== RUN   TestAccPagerDutyServiceIntegration_import
=== RUN   TestAccPagerDutyService_import
=== RUN   TestAccPagerDutyServiceWithIncidentUrgency_import
=== RUN   TestAccPagerDutyTeamMembership_import
=== RUN   TestAccPagerDutyTeam_import
=== RUN   TestAccPagerDutyUser_import
=== RUN   TestProvider
--- PASS: TestProvider (0.00s)
=== RUN   TestProviderImpl
--- PASS: TestProviderImpl (0.00s)
=== RUN   TestAccPagerDutyAddon_Basic
=== RUN   TestAccPagerDutyEscalationPolicy_Basic
=== RUN   TestAccPagerDutyEscalationPolicyWithTeams_Basic
=== RUN   TestAccPagerDutyMaintenanceWindow_Basic
=== RUN   TestAccPagerDutySchedule_Basic
=== RUN   TestAccPagerDutyScheduleOverflow_Basic
=== RUN   TestAccPagerDutySchedule_BasicWeek
=== RUN   TestAccPagerDutySchedule_Multi
=== RUN   TestAccPagerDutyServiceIntegration_Basic
=== RUN   TestAccPagerDutyServiceIntegrationGeneric_Basic
=== RUN   TestAccPagerDutyService_Basic
=== RUN   TestAccPagerDutyService_BasicWithIncidentUrgencyRules
=== RUN   TestAccPagerDutyService_FromBasicToCustomIncidentUrgencyRules
=== RUN   TestAccPagerDutyTeamMembership_Basic
=== RUN   TestAccPagerDutyTeam_Basic
=== RUN   TestAccPagerDutyUser_Basic
=== RUN   TestAccPagerDutyUserWithTeams_Basic
--- PASS: TestAccPagerDutyTeam_Basic (10.94s)
--- PASS: TestAccPagerDutySchedule_Multi (14.74s)
--- PASS: TestAccPagerDutyUser_Basic (15.11s)
--- PASS: TestAccPagerDutyTeamMembership_Basic (15.75s)
--- PASS: TestAccDataSourcePagerDutyEscalationPolicy_Basic (16.26s)
--- PASS: TestAccPagerDutyService_FromBasicToCustomIncidentUrgencyRules (21.50s)
--- PASS: TestAccPagerDutyService_BasicWithIncidentUrgencyRules (21.79s)
--- PASS: TestAccPagerDutyMaintenanceWindow_Basic (26.96s)
--- PASS: TestAccPagerDutyScheduleOverflow_Basic (16.32s)
--- PASS: TestAccPagerDutySchedule_BasicWeek (16.88s)
--- PASS: TestAccPagerDutyUserWithTeams_Basic (21.87s)
--- PASS: TestAccPagerDutySchedule_Basic (17.29s)
--- PASS: TestAccPagerDutyService_Basic (15.99s)
--- PASS: TestAccPagerDutyService_import (10.77s)
--- PASS: TestAccPagerDutyServiceIntegrationGeneric_Basic (23.74s)
--- PASS: TestAccPagerDutyUser_import (7.98s)
--- PASS: TestAccPagerDutyAddon_Basic (8.31s)
--- PASS: TestAccPagerDutyTeam_import (5.10s)
--- PASS: TestAccPagerDutyServiceIntegration_Basic (24.48s)
--- PASS: TestAccPagerDutyEscalationPolicyWithTeams_Basic (16.40s)
--- PASS: TestAccPagerDutyTeamMembership_import (10.13s)
--- PASS: TestAccPagerDutyEscalationPolicy_Basic (16.27s)
--- PASS: TestAccPagerDutyServiceWithIncidentUrgency_import (10.60s)
--- PASS: TestAccDataSourcePagerDutyVendor_Basic (4.32s)
--- PASS: TestAccPagerDutyEscalationPolicy_import (11.31s)
--- PASS: TestAccPagerDutySchedule_import (10.98s)
--- PASS: TestAccPagerDutyServiceIntegration_import (14.31s)
--- PASS: TestAccDataSourcePagerDutyUser_Basic (8.91s)
--- PASS: TestAccPagerDutyMaintenanceWindow_import (13.59s)
--- PASS: TestAccDataSourcePagerDutySchedule_Basic (11.66s)
PASS
ok  	github.com/terraform-providers/terraform-provider-pagerduty/pagerduty	59.939s

[grubernaut]

LGTM, nice work here!

[99]

hi @heimweh is it possible to deploy this fix ?