Failed patch could left source code partially changed

### Problem
When a patch failed to apply to the source code this could be left partially changed.

### Description

If a patch modify more than a file it could happens that it successfully applies to the first `n` files and then fails when reaching the `n+1` file. In this case there isn't any rollback and the `n` modified files are left edited.

### Expected behaviour

If a patch fails to apply the target source code should be left unchanged.