Add close() method in MasterSlaveConnection.php

[ghost]

MasterSlaveConnection would use parent::close() to close connection, and it would close master connection, but slave connection.

That will increase the sqlite connections, and occur the "too many open files" error when I run our test.

[doctrinebot]

Hello,

thank you for creating this pull request. However did not open it on the "master"
branch. Our Git workflow requires all pull requests to go through "master" branch
and the release masters then merge them back into stable branches, if they are
bug fixes.

Please open the pull request again for the "master" branch and close
this one.

Nevertheless I have opened a Jira ticket for this Pull Request to track this
issue:

http://www.doctrine-project.org/jira/browse/DBAL-963

We use Jira to track the state of pull requests and the versions they got
included in.

[Ocramius]

@accdavid does that also happen when you remove all references to the MasterSlaveConnection? This looks like a GC issue

[deeky666]

@Ocramius this is a backport. It is already implemented like this in master. So I don't see any problems with merging this.

[Ocramius]

@deeky666 excellent. Merging