fix path for profitbricks list_snapshots() method
fix path for profitbricks list_snapshots() method

leading slash breaks the URL

Signed-off-by: Quentin Pradet <d17611fde61d73f8de1b8b01bc47d446558ccd8e@apache.org>

ByteInternet/libcloud,mistio/libcloud,ByteInternet/libcloud,apache/libcloud,andrewsomething/libcloud,StackPointCloud/libcloud,andrewsomething/libcloud,Kami/libcloud,vongazman/libcloud,apache/libcloud,pquentin/libcloud,pquentin/libcloud,mistio/libcloud,Kami/libcloud,Kami/libcloud,StackPointCloud/libcloud,Scalr/libcloud,mistio/libcloud,Scalr/libcloud,ByteInternet/libcloud,apache/libcloud,pquentin/libcloud,Scalr/libcloud,StackPointCloud/libcloud,andrewsomething/libcloud,vongazman/libcloud,vongazman/libcloud