iocInit: no need to break DB_LINK when isolated

This is being done to free the link private struct,
but dbDbRemoveLink() is not used to avoid the overhead
of splitting every lockset just before the PDB
is free'd.

No reason to do this for non-isolated until scans threads
are stopped.

src/ioc/misc/iocInit.c

@@ -643,7 +643,7 @@ static void doCloseLinks(dbRecordType *pdbRecordType, dbCommon *precord,
             }
             dbCaRemoveLink(NULL, plink);
 
-        } else if (plink->type == DB_LINK) {
+        } else if (iocBuildMode==buildIsolated && plink->type == DB_LINK) {
             /* free link, but don't split lockset like dbDbRemoveLink() */
             free(plink->value.pv_link.pvt);
             plink->type = PV_LINK;