wraster: Remove duplicate code
Duplicating things makes maintenance error-prone, which is not a good idea.
In case the abort procedure would need an update, it would be easy then
to forget some place, leading to leaks, if not worse.
Beside, goto is not as bad as academics would like people to believe, when
it is used correctly (and this case is one of them).
The name for the label was given an explicit meaning to make code easy to
understand.
Signed-off-by: Christophe CURIS <christophe.curis@free.fr>