Fixed PHP-858: Crash when extending Mongo and MongoClient classes and not calling its constructor
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Merged Pull Request #490

* pull-request/490:
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  Fixed PHP-858: Crash when extending Mongo and MongoClient classes and not calling its constructor
Merge branch 'v1.4'

* v1.4:
  Add a comment why this check is needed, as per PR review
  Fixed PHP-858: Crash when extending Mongo and MongoClient classes and not calling its constructor