Address: Service DS not locating queried name when is not in first page of results

[imjaroiswebdev]

Closes #872

Following GH Gist should work to validate the issue is patched.

Acceptance tests results...

TF_ACC=1 go test $(go list ./... |grep -v 'vendor') -v -count=1 -run TestAccDataSourcePagerDutyService -timeout 120m
?       github.com/PagerDuty/terraform-provider-pagerduty       [no test files]
=== RUN   TestAccDataSourcePagerDutyService_Basic
--- PASS: TestAccDataSourcePagerDutyService_Basic (16.10s)
=== RUN   TestAccDataSourcePagerDutyService_HasNoTeam
--- PASS: TestAccDataSourcePagerDutyService_HasNoTeam (14.24s)
=== RUN   TestAccDataSourcePagerDutyService_HasOneTeam
--- PASS: TestAccDataSourcePagerDutyService_HasOneTeam (15.44s)
PASS
ok      github.com/PagerDuty/terraform-provider-pagerduty/pagerduty     46.741s
testing: warning: no tests to run
PASS
ok      github.com/PagerDuty/terraform-provider-pagerduty/pagerdutyplugin       1.158s [no tests to run]
testing: warning: no tests to run
PASS
ok      github.com/PagerDuty/terraform-provider-pagerduty/util  1.146s [no tests to run]