merged branch Burgov/hint_about_mime_type_guesser_2_0 (PR #2843)

Commits
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45bba7b Added a hint about a possible cause for why no mime type guesser is be available

Discussion
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Added a hint about a possible cause for why no mime type guesser is be available

Bug fix: no
Feature addition: yes
Backwards compatibility break: no
Symfony2 tests pass: yes

src/Symfony/Component/HttpFoundation/File/MimeType/MimeTypeGuesser.php

@@ -111,7 +111,7 @@ class MimeTypeGuesser implements MimeTypeGuesserInterface
         }
 
         if (!$this->guessers) {
-            throw new \LogicException('Unable to guess the mime type as no guessers are available.');
+            throw new \LogicException('Unable to guess the mime type as no guessers are available (Did you enable the php_fileinfo extension?)');
         }
 
         foreach ($this->guessers as $guesser) {