Fix typo - Drop extra slash in uri returned by sr.ls
Fix typo - Drop extra slash in uri returned by sr.ls

sr.ls() should not return a different uri than volume.create(),
.clone and .snapshot.

Signed-off-by: Robert Breker <bfcd7039ca4b92386f0756a1d5e67ea4ff23cfe0@citrix.com>

xapi-project/ffs