New changes to gstvideo will reset all the video info state
when calling _set_format, overwriting what was previously set
in the preceding code.
The comment says the following code is meant to preserve the
pre-crop size, so let's just keep the size and related data
as this does not seem to break anything else (this is what
the _set_format call would have set before the change that
reset all data, except the colorimetry).
6b887060b1