[Form] Fixed: Added "validation_groups" option to submit button
merged branch bschussek/fix-submit (PR #8764)

This PR was merged into the 2.3 branch.

Discussion
----------

[Form] Fixed: Added "validation_groups" option to submit button

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #8209
| License       | MIT
| Doc PR        | -

Commits
-------

c342715 [Form] Fixed: Added "validation_groups" option to submit button
[HttpKernel] removed unused variable
Added sleep() workaround for windows php rename bug
merged branch caponica/cache-clear-win-workaround (PR #8767)

This PR was submitted for the master branch but it was merged into the 2.2 branch instead (closes #8767).

Discussion
----------

Added sleep() workaround for windows php rename bug

For more info see links in issue #8766

Commits
-------

b3c815b Added sleep() workaround for windows php rename bug
Merge branch '2.2' into 2.3

* 2.2:
  Added sleep() workaround for windows php rename bug
  [HttpKernel] removed unused variable

Conflicts:
	src/Symfony/Component/HttpKernel/Kernel.php