updated VERSION for 2.2.6
bumped Symfony version to 2.2.7
[HttpKernel] changed fragment URLs to be relative by default (closes #8458)
Merge branch '2.2' into 2.3

* 2.2:
  [Security] fixed some phpdoc
  Fixed PHPDoc Blocks
  optimized circular reference checker
  [HttpKernel] changed fragment URLs to be relative by default (closes #8458)