Fix mapping creation on bulk request

When a bulk request triggers an index creation a mapping might not be
created. The reason is that when indexing documents in a bulk,
an indexing operation might fail due to a shard not yet being
started. The mapping service, however, might already
have the mapping but the mapping update is never issued to the master,
even on subsequent indexing of documents.

Instead, the mapping must be propagated to master even if the
indexing fails due to a shard not being started.