Update Upgrade.md after minor bc break in 2.5.0

[tkleinhakisa]

The introduction of the second parameter in EntityRepository#createQueryBuilder generates a runtime notice if you have a sub-class of EntityRepository that has a second parameter in the createQueryBuilder method

The parameter was introduced in b0513a7

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[Ocramius]

@tkleinhakisa I think the BC break should be reverted, and we should use func_get_args() for the 2.5.x series, while we keep the current code for 2.6.x

[tkleinhakisa]

@Ocramius I thiink i made a mistake and the break was introduced in 2.5.0 not 2.5.1

In this case the param should be kept and the upgrade 2.5 updated, is that right ?

[Ocramius]

@tkleinhakisa if the BC break happened from 2.4.x -> 2.5.0 then this patch is correct, and no reverting is needed.

[Ocramius]

Move to the 2.5 block

[tkleinhakisa]

Fixed and rebased

[guilhermeblanco]

Thanks for the PR!

This is now merged in 2.5 and master branches.