Regression: NPE in Admin GUI editing CVC CA that was created before validators

I have an old CVCA in my system. Trying to edit this CA results in an NPE in the Admin GUI.

16:27:15,336 INFO [org.cesecore.audit.impl.log4j.Log4jDevice] (default task-89) 2017-12-18 16:27:15+01:00;ACCESS_CONTROL;SUCCESS;ACCESSCONTROL;CORE;CN=SuperAdmin;;;;resource0=/cryptotoken/view/459472142
16:27:15,487 ERROR [errorpage.jsp] (default task-89) null: java.lang.NullPointerException
at org.apache.jsp.ca.editcas.editcas_jsp._jspService(editcas_jsp.java:5483)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)

Looking into editcas.jsp, it is this code:

if(editca && usedKeyValidators.contains(validatorId))

Let CAInfo check for null and never return null for getValidators().