When there's only one batch, use it

On all decrease cases (where BatchDecreaseSelectionDialog is used) and on
inventory, if there's only one batch of that storable, use it directly instead
of running the batch selection dialog.

Change-Id: I5f66785416d79cbd6d90392247bec4365bdc6d93
Fixes: http://bugs.async.com.br/show_bug.cgi?id=5554
Merge "When there's only one batch, use it"