Function score query: Add missing whitespace when throwing exception

DecayFunctionParser throws a parse exception with a string containing "scaleand origin", this fixes the spacing issue.

src/main/java/org/elasticsearch/index/query/functionscore/DecayFunctionParser.java

@@ -200,7 +200,7 @@ public abstract class DecayFunctionParser implements ScoreFunctionParser {
             }
         }
         if (!scaleFound || !refFound) {
-            throw new ElasticsearchParseException("Both " + DecayFunctionBuilder.SCALE + "and " + DecayFunctionBuilder.ORIGIN
+            throw new ElasticsearchParseException("Both " + DecayFunctionBuilder.SCALE + " and " + DecayFunctionBuilder.ORIGIN
                     + " must be set for numeric fields.");
         }
         IndexNumericFieldData numericFieldData = parseContext.getForField(mapper);