Dvc: Try to repro imported files if cache unavialable

[pared]

Source

@verasativa tried pulling project, while import-url-ed data was not in the cache. Maybe we should consider doing dvc repro if stage stands for imported file and data is not avialable inside cache?

reproduction script:

#!/bin/bash

rm -rf repo storage
mkdir repo storage

pushd repo

git init >> /dev/null && dvc init -q
dvc remote add -d rmt ../storage

dvc import-url https://helpx.adobe.com/content/dam/help/en/stock/how-to/visual-reverse-image-search/jcr_content/main-pars/image/visual-reverse-image-search-v2_intro.jpg img.jpg

rm img.jpg
rm -rf .dvc/cache

dvc pull img.jpg.dvc

[ghost]

@pared , git init also has a --quiet option