tests: sleep(1) before modifying data files
tests: sleep(1) before modifying data files

This will help simulate realistic behaviour on filesystems with poor mtime resolution.

Signed-off-by: Ruslan Kuprieiev <f6538312ce47017d734b1357aabc970ebf896e32@gmail.com>

efiop/dvc,dmpetrov/dataversioncontrol,dataversioncontrol/dvc,dataversioncontrol/dvc,dmpetrov/dataversioncontrol,efiop/dvc