Remove duplicated javadoc fieldType param

Author: dakrone

server/src/main/java/org/elasticsearch/index/mapper/MetadataFieldMapper.java

@@ -37,8 +37,6 @@ public interface TypeParser extends Mapper.TypeParser {
 
         /**
          * Get the default {@link MetadataFieldMapper} to use, if nothing had to be parsed.
-         * @param fieldType null if this is the first root mapper on this index, the existing
-         *                  fieldType for this index otherwise
          * @param fieldType      the existing field type for this meta mapper on the current index
          *                       or null if this is the first type being introduced
          * @param parserContext context that may be useful to build the field like analyzers