#2668 replace with orElse

src/main/java/org/codelibs/fess/api/BaseJsonApiManager.java

.../org/codelibs/fess/app/web/admin/searchlist/ListForm.java

src/main/java/org/codelibs/fess/app/web/base/SearchForm.java

src/main/java/org/codelibs/fess/helper/UserInfoHelper.java

src/main/java/org/codelibs/fess/taglib/FessFunctions.java

src/main/java/org/codelibs/fess/util/WebApiUtil.java