bumped Symfony version to 2.3.15
Revert "bug #10908 [HttpFoundation] implement session locking for PDO (Tobion)"

This reverts commit 8c71454f47bbcdf82693a0501acac3e8fe6e08cf, reversing
changes made to 735e9a4768962b6d5098733c347cff0df6b9cd36.
Merge branch '2.3' into 2.4

* 2.3:
  Revert "bug #10908 [HttpFoundation] implement session locking for PDO (Tobion)"
  bumped Symfony version to 2.3.15
  updated VERSION for 2.3.14
  update CONTRIBUTORS for 2.3.14
  updated CHANGELOG for 2.3.14

Conflicts:
	src/Symfony/Component/HttpKernel/Kernel.php
Merge branch '2.4'

* 2.4:
  Revert "bug #10908 [HttpFoundation] implement session locking for PDO (Tobion)"
  bumped Symfony version to 2.3.15
  updated VERSION for 2.3.14
  update CONTRIBUTORS for 2.3.14
  updated CHANGELOG for 2.3.14
[HttpFoundation] implement session locking for PDO
updated CHANGELOG for 2.3.15
updated VERSION for 2.3.15
bumped Symfony version to 2.3.16
[Process] Fix conflicts between latest 2.3 fix and 2.5 deprecation
bug #10971 [Process] Fix conflicts between latest 2.3 fix and 2.5 deprecation (romainneutron)

This PR was merged into the 2.3-dev branch.

Discussion
----------

[Process] Fix conflicts between latest 2.3 fix and 2.5 deprecation

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

As reported in https://github.com/symfony/symfony/pull/10932#issuecomment-43939786, it's been introduced when merging 2.3 in master

Commits
-------

3454d60 [Process] Fix conflicts between latest 2.3 fix and 2.5 deprecation
updated CHANGELOG for 2.4.5
updated VERSION for 2.4.5
[Process] Deprecate using values that are not string for Process::setStdin and ProcessBuilder::setInput
bumped Symfony version to 2.4.6
feature #10930 [Process] Deprecate using values that are not string for Process::setStdin and ProcessBuilder::setInput (romainneutron)

This PR was merged into the 2.4-dev branch.

Discussion
----------

[Process] Deprecate using values that are not string for Process::setStdin and ProcessBuilder::setInput

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

This deprecates passing a `Process` input any value that is not a strict string. This needs #10929 to be merged.
I don't know if the use of `trigger_error` is correct or should be removed.

Commits
-------

9887b83 [Process] Deprecate using values that are not string for Process::setStdin and ProcessBuilder::setInput
updated version to 2.6
[DomCrawler] Fixed a forgotten case of complex XPath queries
bug #10987 [DomCrawler] Fixed a forgotten case of complex XPath queries (stof)

This PR was merged into the 2.3 branch.

Discussion
----------

[DomCrawler] Fixed a forgotten case of complex XPath queries

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #10986
| License       | MIT
| Doc PR        | n/a

This fixes the case I forgot when rewritting the XPath to avoid making it produce invalid queries. I ran the new tests against the old implementation first, to ensure they cover the BC properly.

I could have detected it by running the Mink 1.5 testsuite with the new code (which is the case for people reporting the bug), but I only ran it for Mink 1.6 which does not produce such XPath anymore.

Commits
-------

a9de61e [DomCrawler] Fixed a forgotten case of complex XPath queries
[Debug] preserve modified error level
[Debug] throw even in stacking mode to preserve code paths