storage: Fix makedirs() invocation for Python 2
storage: Fix makedirs() invocation for Python 2

Revert this part of commit a61672abcbe so that it continues to work on
RHEL 7, i. e. with Python 2.

Closes #11986

deryni/cockpit,cockpit-project/cockpit,garrett/cockpit,martinpitt/cockpit,cockpit-project/cockpit,deryni/cockpit,moraleslazaro/cockpit,cockpit-project/cockpit,garrett/cockpit,martinpitt/cockpit,cockpituous/cockpit,garrett/cockpit,moraleslazaro/cockpit,moraleslazaro/cockpit,cockpituous/cockpit,cockpituous/cockpit,moraleslazaro/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,mvollmer/cockpit,cockpituous/cockpit,cockpituous/cockpit,garrett/cockpit,martinpitt/cockpit,moraleslazaro/cockpit,martinpitt/cockpit,cockpituous/cockpit,moraleslazaro/cockpit,deryni/cockpit,moraleslazaro/cockpit,deryni/cockpit,deryni/cockpit,mvollmer/cockpit,mvollmer/cockpit,mvollmer/cockpit,martinpitt/cockpit,garrett/cockpit,mvollmer/cockpit,deryni/cockpit,deryni/cockpit