Updated php55-mongo to 1.6.14.

>From Bartosz Kuzma in PR 51306.

1.6.14
** Bug
* [PHP-1468] - Segfault on node with high network latency
* [PHP-1511] - append_getlasterror() should ignore unset fsync/journal from link

** Improvement
* [PHP-1510] - Route unacknowledged writes through legacy op codes

1.6.13
** Bug
* [PHP-1483] - GridFS file storage fails on big endian platform
* [PHP-1500] - Socket timeout not applied to initial command cursor query
* [PHP-1501] - Rephrase unsupported/corrupt BSON messages
* [PHP-1504] - Segfault connecting to authenticated RS after non-auth connections
* [PHP-1505] - negative files.length when storing file with size > 2GB in gridfs

1.6.12
** Bug
* [PHP-1494] - We don't allocate enough space for the hash buffer

** Task
* [PHP-1474] - Declare no support for PHP 7

1.6.11
** Bug
* [PHP-1467] - PHP driver on big endian platform not connecting to MongoDB

1.6.10
** Bug
* [PHP-1460] - Query with limit leaves open cursors on server
* [PHP-1462] - Fix static compilation
* [PHP-1464] - GridFS should not drop dupes when creating index

(wiz)