minor symfony#16691 [DI] remove useless condition around unset (Tobion)

This PR was merged into the 2.3 branch.

Discussion
----------

[DI] remove useless condition around unset

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

Commits
-------

478375d [DI] remove useless condition around unset

Author: fabpot

src/Symfony/Component/DependencyInjection/Container.php

@@ -312,10 +312,7 @@ public function get($id, $invalidBehavior = self::EXCEPTION_ON_INVALID_REFERENCE
                 $service = $this->$method();
             } catch (\Exception $e) {
                 unset($this->loading[$id]);
-
-                if (array_key_exists($id, $this->services)) {
-                    unset($this->services[$id]);
-                }
+                unset($this->services[$id]);
 
                 if ($e instanceof InactiveScopeException && self::EXCEPTION_ON_INVALID_REFERENCE !== $invalidBehavior) {
                     return;

src/Symfony/Component/DependencyInjection/Definition.php

@@ -409,9 +409,7 @@ public function hasTag($name)
      */
     public function clearTag($name)
     {
-        if (isset($this->tags[$name])) {
-            unset($this->tags[$name]);
-        }
+        unset($this->tags[$name]);
 
         return $this;
     }