Ensure file basepath exists
Ensure file basepath exists

On a manual gnocchi install, i run into OSError on
/var/lib/gnocchi/measure. This is because the basepath
doesnt exist yet. On devstack this is handled. But we should
handle it if gnocchi is installed manually.

Change-Id: Iabe00a7cadede851ea3147d98bc2eba0708f92c3

sileht/gnocchi,sileht/gnocchi,gnocchixyz/gnocchi,leandroreox/gnocchi,gnocchixyz/gnocchi,leandroreox/gnocchi