Wrong charset for file_managed.uri causes Integrity constraint violation when inserting two filenames with different casing. [#1475124]

To reproduce:

Create two files on your desktop 'tree.jpg' and 'Tree.jpg' in separate folders.
On a Linux installation (or another case-sensitive file system) of Drupal, open a (new) node that has a field of type 'file'
Add the file 'tree.jpg' (don't save yet)
Then add the file 'Tree.jpg'

Now you get the following error:

PDOException: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry 'public://Bomen.jpg' for key 2: INSERT INTO {file_managed} (uid, filename, uri, filemime, filesize, status, timestamp) VALUES (:db_insert_placeholder_0, :db_insert_placeholder_1, :db_insert_placeholder_2, :db_insert_placeholder_3, :db_insert_placeholder_4, :db_insert_placeholder_5, :db_insert_placeholder_6); Array
(
[:db_insert_placeholder_0] =&gt; 1
[:db_insert_placeholder_1] =&gt; Bomen.jpg
[:db_insert_placeholder_2] =&gt; public://Bomen.jpg
[:db_insert_placeholder_3] =&gt; image/jpeg
[:db_insert_placeholder_4] =&gt; 770042
[:db_insert_placeholder_5] =&gt; 0
[:db_insert_placeholder_6] =&gt; 1331298860
)

(notice I used the files bomen.jpg and Bomen.jpg, the Dutch translation of trees ;-))

The error is obviously due to the fact that the column file_managed.uri is case insensitive (collation utf_general_ci) whereas it should have a case sensitive collation.

Solution: change the column to utf8_bin. This collation is case sensitive.