`git stash pop` is executed when it should not be

[dank-openai]

I run a command like stack-pr export -B HEAD~2~4 -H HEAD~2 and it works (e.g. it pushes changes and creates & updates PRs) right up until the end, when it needlessly performs git stash pop:

SUCCESS!
Running: ['git', 'stash', 'pop']
Auto-merging <some file>
CONFLICT (content): Merge conflict in <some file>

This is wrong. There was no reason to git stash pop. Furthermore, my git stash has some things that I placed there, which cause a merge conflict (as seen above).

What I notice is that near the beginning of the command's execution is:

Running: ['git', 'stash', 'save']
No local changes to save

Solution: when any command (such as export) performs stash, it must pay attention to the stash save result. If no changes were saved, then it must not later stash pop.

[ZolotukhinM]

Fixed in #101