minor #7122 Remove "Symfony3 will use" (alexislefebvre, javiereguiluz)

This PR was submitted for the 3.1 branch but it was merged into the 2.7 branch instead (closes #7122).

Discussion
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Remove "Symfony3 will use"

Since Symfony 3 has been released, using "will" is unnecessary

Commits
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e00ba0b Revert "Updated the contents for the new Symfony 3 dir structure"
0022165 Updated the contents for the new Symfony 3 dir structure
65127c9 Remove "Symfony3 will use"

Author: xabbuh

best_practices/creating-the-project.rst

@@ -157,8 +157,7 @@ structure of Symfony, you can
 :doc:`override the location of the main directories </configuration/override_dir_structure>`:
 ``cache/``, ``logs/`` and ``web/``.
 
-In addition, Symfony3 will use a slightly different directory structure when
-it's released:
+In addition, Symfony3 uses a slightly different directory structure:
 
 .. code-block:: text