Add backticks around collation to avoid query error

Encountered the following when running `./bin/storage upgrade`, with MySQL 5.1.67:

    [2014-10-05 17:59:48] EXCEPTION: (AphrontQueryException) #1064: You have an error in your SQL
    syntax; check  the manual that corresponds to your MySQL server version for the right syntax to
    use near 'binary' at line 1 at
    [<phutil>/src/aphront/storage/connection/mysql/AphrontBaseMySQLDatabaseConnection.php:308]

The offending queries all contained `...COLLATE binary'. Adding backticks around "binary" solves the error and allows the migrations to run.