storage: Don't lie about path used to look up in error message

storage: Don't lie about path used to look up in error message

In storageVolLookupByPath the provided path is "sanitized" at first.
This removes some extra slashes and stuff. When the lookup of the volume
fails the original path is used which makes it hard to trace errors in
some cases.

Improve the error message to print the sanitized path along with the
user provided path if they are not equal.