Retry send_nsca in govuk_env_sync.sh
Retry send_nsca in govuk_env_sync.sh

Sometimes this might fail, so retry to avoid Icinga checks failing
spuriously.

alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet