Fix 500 when deleting mobile numbers
Merge branch 'master' into delete_phone_500
Correct issues with fix for deleting phone numbers

Response to comments on pull request
https://github.com/dimagi/commcare-hq/pull/224
Merge branch 'master' into delete_phone_500
Use correct return type for get_time_zone()
Merge pull request #224 from dimagi/delete_phone_500

Fix 500 when deleting mobile numbers