set default 'ignore mapping' option for java generators with 'false' value

Author: HugoMario

modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AbstractJavaCodegen.java

@@ -1579,9 +1579,4 @@ public String sanitizeTag(String tag) {
         }
         return tag;
     }
-
-    public boolean defaultIgnoreImportMappingOption() {
-        return true;
-    }
-
 }