Atlas-2294: type creation populates description field with empty string when no value is provided

intg/src/main/java/org/apache/atlas/model/typedef/AtlasRelationshipEndDef.java

@@ -126,7 +126,7 @@ public class AtlasRelationshipEndDef implements Serializable {
      *   - whether this is a legacy attribute
      */
     public AtlasRelationshipEndDef(String typeName, String name, Cardinality cardinality, boolean isContainer, boolean isLegacyAttribute) {
-        this(typeName, name, cardinality, isContainer, isLegacyAttribute,"");
+        this(typeName, name, cardinality, isContainer, isLegacyAttribute, null);
     }
     /**
      *

intg/src/main/java/org/apache/atlas/model/typedef/AtlasStructDef.java

@@ -286,7 +286,7 @@ public class AtlasStructDef extends AtlasBaseTypeDef implements Serializable {
 
         public AtlasAttributeDef(String name, String typeName, boolean isOptional, Cardinality cardinality,
                                  int valuesMinCount, int valuesMaxCount, boolean isUnique, boolean isIndexable, List<AtlasConstraintDef> constraints) {
-            this(name, typeName, isOptional, cardinality, valuesMinCount, valuesMaxCount, isUnique, isIndexable, null, constraints, "");
+            this(name, typeName, isOptional, cardinality, valuesMinCount, valuesMaxCount, isUnique, isIndexable, null, constraints, null);
         }
 
         public AtlasAttributeDef(String name, String typeName, boolean isOptional, Cardinality cardinality,