Unique key name isn't correctly set

Example :

<unique-constraints>
<unique-constraint columns="permalink" />
<unique-constraint columns="code" />
</unique-constraints>

This will create :
CREATE UNIQUE INDEX UNIQ_6C3BF144F286BC32 ON shows (permalink);
CREATE UNIQUE INDEX 1 ON shows (code);

instead of :
CREATE UNIQUE INDEX UNIQ_6C3BF144F286BC32 ON shows (permalink);
CREATE UNIQUE INDEX UNIQ_6C3BF14477153098 ON shows (code);

The problem comme from SchemaTool, and the first key is a valid result because of "==" instead of "===" inside Table.php.

I have create a PR on Github.