stage: check if dir exists before calling makedirs
stage: check if dir exists before calling makedirs

Fixes #448

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

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