Fix typo, use module level constant.
Fix typo, use module level constant.

andrewsomething/libcloud,mistio/libcloud,mistio/libcloud,Kami/libcloud,apache/libcloud,mistio/libcloud,apache/libcloud,andrewsomething/libcloud,Kami/libcloud,apache/libcloud,Kami/libcloud,andrewsomething/libcloud