Fix schema search path to find vocabulary

@pbr6cornell @schuemie

The concept_ancestor table is in the vocabulary schema. Apparently (Mark Khayter told me) the table is in the mslr_cdm4 schema (or possibly a view), but that is not the expected behavior and is currently not true for ccae_cdm4. This
commit changes the sql code to refer to the vocabulary schema instead and works with both the mslr_cdm4 and ccae_cdm4 schemas.

Is there any reason why this change shouldn't be made? I have only tested it in the redshift database, so this change may not be quite right, but I'm not familiar enough with the sql server syntax to be totally sure.