trigger_vds_impute ~ vdswim impute; more logs on vdswim_impute

vdswim impute finished, so I added more log statements to prove to
myself that it finished properly

modified trigger_vds_impute to mirror how vdswim impute runs through
getting files, processing them.  There are a lot of statements that
there are missing imputation files, so I want to run it *yet again* to
make sure I'm not missing things I should already have.