getMeta of a deleted item breaks get(DELETED_VALUE)

The following sequence of operations should work, but the final GET fails.

• store(key1, <xattr_value>);
• delete(key1); <- system xattrs remain
• get_meta(key1)
• get(key1, GET_DELETED_VALUE) <- should return system xattrs, but fails with KEY_ENOENT

The issue is that the get_meta leaves a "temp deleted" StoredValue in the hash table for key1 and our get code enters a failure path for items in that state regardless of the GET_DELETED_VALUE option.

This impacts SubDoc (and mobile). SubDoc allows the retrieval of system xattrs for deleted documens and will unexpectedly fail if a sequence as above occurs.