pingdom_contact data source returns wrong ID

[messiahUA]

I have data "pingdom_contact" "pagerduty" with the correct name and I see that it finds a proper contact in the terraform debug logs, but in the end, the actual id in the state is different (the last element of contacts list)

[marcelomilera]

I came across the same issue. It seems that there's a small bug when using the "pingdom_contact" data source that always ends up retrieving the last element of the contacts list.
This small PR should solve that #92