Bug 1076: Updated SchemaPath hashcode to behave as previously.

Change in hashCode of SchemaPath uncovered other issue
where code was expecting sorted set from HashSet.

Updated hashCode to behave as previously defined.

Change-Id: I2eea3b5890f985553127e11b50143d7714313ced
Signed-off-by: Tony Tkacik <ttkacik@cisco.com>