[HttpFoundation] use different approach for duplicate keys in postgres, fix merge for sqlsrv and oracle
updated CHANGELOG for 2.3.16
update CONTRIBUTORS for 2.3.16
updated VERSION for 2.3.16
updated CHANGELOG for 2.4.6
updated VERSION for 2.4.6
Fix a parameter name in a test
bumped Symfony version to 2.3.17
bumped Symfony version to 2.4.7
minor #11026 [Validator] Fix a parameter name in a test (elnur)

This PR was merged into the 2.3 branch.

Discussion
----------

[Validator] Fix a parameter name in a test

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | none
| License       | MIT
| Doc PR        | not required

Commits
-------

069e925 Fix a parameter name in a test
Remove undefined variable $e
bug #11041 Remove undefined variable $e (skydiablo)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #11041).

Discussion
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Remove undefined variable $e

This PR was submitted on the symfony/DependencyInjection read-only repository and moved automatically to the main Symfony repository (closes symfony/DependencyInjection#6).

Commits
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637c6e1 Remove undefined variable $e
Added phpdoc for Cache-Control directives methods
minor #10974 [HttpFoundation] Added PHPDoc for Cache-Control directives methods (tony-co)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #10974).

Discussion
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[HttpFoundation] Added PHPDoc for Cache-Control directives methods

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Commits
-------

58b0aef Added phpdoc for Cache-Control directives methods
fixed previous merge
[Doctrine Bridge] fix DBAL session handler according to PdoSessionHandler
bug #11009 [HttpFoundation] smaller fixes for PdoSessionHandler (Tobion)

This PR was merged into the 2.3 branch.

Discussion
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[HttpFoundation] smaller fixes for PdoSessionHandler

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #10652
| License       | MIT

For both the PdoSessionHandler and DbalSessionHandler
- https://github.com/symfony/symfony/pull/10652#issuecomment-42370425: Transactional DELETE + INSERT does not work as expected
- https://github.com/symfony/symfony/pull/10652#issuecomment-44359784: sqlsrv 2005 does not support the MERGE SQL, and if used it requires an HOLDLOCK
- missing time update for sqlsrv and oracle

Commits
-------

a0e1d4d [Doctrine Bridge] fix DBAL session handler according to PdoSessionHandler
00d707f [HttpFoundation] use different approach for duplicate keys in postgres, fix merge for sqlsrv and oracle
[HttpFoundation] fix switch statement
bug #11063 [HttpFoundation] fix switch statement (Tobion)

This PR was merged into the 2.3 branch.

Discussion
----------

[HttpFoundation] fix switch statement

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #11009
| License       | MIT

Commits
-------

da24bc9 [HttpFoundation] fix switch statement
[Bridge][Twig] Replace deprecated features