Log Message:
Update databases/mongo-c-driver to 1.4.0.

- The driver can now use the native TLS and crypto functions
  included in Mac OS X and Windows.
- The driver implements the MongoDB Command Monitoring Spec.
- New functions mongoc_client_set_error_api and
  mongoc_client_pool_set_error_api
  allow applications to distinguish client and server errors.
- Unacknowledged writes (writes whose mongoc_write_concern_t "w"
  value is zero) now reply with an empty document instead of one
  with nInserted: 0, nUpdated: 0, and so on.
- Public API For Higher-Level Drivers
- New connection string option "localThresholdMS".
- zSeries, POWER8, and ARM 64-bit platform support.
- Performance enhancements, reduce allocation and copying in
  command code.
- All man page names now begin with "mongoc_" to avoid install
  conflicts.
- New function mongoc_gridfs_file_set_id.