bug #16365 Add the PHP 7 polyfill for the random_bytes function (pierredup)

This PR was merged into the 2.8 branch.

Discussion
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Add the PHP 7 polyfill for the random_bytes function

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

Some classes (like the `SecureRandom` class) currently depends on the `random_bytes` function, which is only available in the PHP 7 polyfill

Commits
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8ab8ca0 Add the PHP 7 polyfill for the random_bytes function

src/Symfony/Bundle/SecurityBundle/composer.json

@@ -19,7 +19,8 @@
         "php": ">=5.3.9",
         "symfony/security": "~2.8|~3.0.0",
         "symfony/security-acl": "~2.7|~3.0.0",
-        "symfony/http-kernel": "~2.2|~3.0.0"
+        "symfony/http-kernel": "~2.2|~3.0.0",
+        "symfony/polyfill-php70": "~1.0"
     },
     "require-dev": {
         "symfony/browser-kit": "~2.4|~3.0.0",

src/Symfony/Component/Security/Core/composer.json

@@ -19,6 +19,7 @@
         "php": ">=5.3.9",
         "symfony/polyfill-php55": "~1.0",
         "symfony/polyfill-php56": "~1.0",
+        "symfony/polyfill-php70": "~1.0",
         "symfony/polyfill-util": "~1.0"
     },
     "require-dev": {

src/Symfony/Component/Security/Csrf/composer.json

@@ -18,6 +18,7 @@
     "require": {
         "php": ">=5.3.9",
         "symfony/polyfill-php56": "~1.0",
+        "symfony/polyfill-php70": "~1.0",
         "symfony/security-core": "~2.4|~3.0.0"
     },
     "require-dev": {