Coverity: dereference null value in PermissionMapperDefinitions (Elytron subsystem)

Coverity static-analysis scan found a possilbe method call on null object in the PermissionMapperDefinitions.createPermission method.

https://scan7.coverity.com/reports.htm#v16159/p12663/fileInstanceId=6892117&defectInstanceId=1794524&mergedDefectId=1388481

Module currentModule = Module.getCallerModule();
if (permission.getModule() != null) {
    ModuleIdentifier mi = ModuleIdentifier.fromString(permission.getModule());
    try {
        currentModule = currentModule.getModule(mi);

The currentModule value returned from Module.getCallerModule() may be null. The getModule() method is called on it without the null-check.