do not write an empty failreason in case that there is no fail. Because

of the lazy instantiation rule this value was not actually written, but
if lazy instantiation is switched on, then this causes that all crawl
starts delete all crawl-start-hosts completely because this looks for
filled error reasons.

source/net/yacy/search/schema/CollectionConfiguration.java

@@ -201,7 +201,6 @@ public class CollectionConfiguration extends SchemaConfiguration implements Seri
         final DigestURI digestURI = md.url();
         boolean allAttr = this.isEmpty();
 
-        if (allAttr || contains(CollectionSchema.failreason_s)) add(doc, CollectionSchema.failreason_s, "");
         add(doc, CollectionSchema.id, ASCII.String(md.hash()));
         String us = digestURI.toNormalform(true);
         add(doc, CollectionSchema.sku, us);
@@ -354,7 +353,6 @@ public class CollectionConfiguration extends SchemaConfiguration implements Seri
         Set<ProcessType> processTypes = new LinkedHashSet<ProcessType>();
         
         add(doc, CollectionSchema.id, id);
-        if (allAttr || contains(CollectionSchema.failreason_s)) add(doc, CollectionSchema.failreason_s, ""); // overwrite a possible fail reason (in case that there was a fail reason before)
         String docurl = digestURI.toNormalform(true);
         add(doc, CollectionSchema.sku, docurl);