Exit with an error in the Rake import task when the index as not crea…

…ted in elasticsearch

Previously, when the index could not be created due to eg. error in mapping,
it was silently ignored and data were still indexed (with dynamic mapping).

This was a source of hard-to-pin-down errors. When there's an error while
creating the index, the Rake task will exit(1) and print the HTTP response, now.

Closes karmi#392

lib/tire/tasks.rb

@@ -54,7 +54,11 @@ def elapsed_to_human(elapsed)
     unless index.exists?
       mapping = MultiJson.encode(klass.tire.mapping_to_hash, :pretty => Tire::Configuration.pretty)
       puts "[IMPORT] Creating index '#{index.name}' with mapping:", mapping
-      index.create :mappings => klass.tire.mapping_to_hash, :settings => klass.tire.settings
+      unless index.create( :mappings => klass.tire.mapping_to_hash, :settings => klass.tire.settings )
+        STDERR.puts "[ERROR] There has been an error when creating the index -- elasticsearch returned:",
+                    index.response
+        exit(1)
+      end
     end
 
     STDOUT.sync = true