minor #891 Move the placeholder for assets version in config.yml (kachkaev)

This PR was submitted for the master branch but it was merged into the 2.7 branch instead (closes #891).

Discussion
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Move the placeholder for assets version in config.yml

Uncommenting ’#assets_version: SomeVersionScheme’ will cause an exception in Symfony 2.7+ The parameter was moved to framework -> asserts.

Commits
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d1cafee Move the placeholder for assets version in config.yml

Author: fabpot

app/config/config.yml

@@ -21,7 +21,6 @@ framework:
     #serializer:      { enable_annotations: true }
     templating:
         engines: ['twig']
-        #assets_version: SomeVersionScheme
     default_locale:  "%locale%"
     trusted_hosts:   ~
     trusted_proxies: ~