Avoid writing empty multipolygons to spatialindex.
Otherwise postgres causes GeoNetwork to fail on restart with
exception as follows:

org.postgresql.util.PSQLException: ERROR: geometry contains non-closed rings
Don't cause an exception if the schemaLocation is not defined for
a schema - just log an error that we don't have a schemaLocation
Relax validation on responses and records in oaipmh - seems that most
oaipmh servers actually return mildly broken responses so its best to
try to continue rather than just give up at the first invalid response
Merge remote-tracking branch 'upstream/2.10.x' into 2.10.x