[FIX] ir.translation: translated terms within view definitions were not loaded

[FIX] ir.translation: translated terms within view definitions were not loaded

The changes for QWeb template translation have introduced
res_id values in PO comments for all `#: view:` terms, as
the real database id needs to be resolved when loading them.

For non-QWeb views this is not necessary and actually caused
the terms to be dropped when the res_id could not be resolved.

Rather than having a different PO comment format for QWeb and
non-QWeb views, we can extend the QWeb hack to force the
res_id to 0 for non-QWeb views.

Fixes issue #1755