Fixing NPE on switching from Birthday to Anniversary event type

The code is trying to ensure that a year is provided
(which is not required for a birthday).  The value
may be null or an empty string.

Bug: 3314819
Change-Id: If76731316e581addeeca9427adcf204eec7e5199
diff --git a/src/com/android/contacts/editor/EventFieldEditorView.java b/src/com/android/contacts/editor/EventFieldEditorView.java
index c386812..5a7fe36 100644
--- a/src/com/android/contacts/editor/EventFieldEditorView.java
+++ b/src/com/android/contacts/editor/EventFieldEditorView.java
@@ -179,7 +179,7 @@
         // Check whether the year is optional
         final boolean isYearOptional = getType().isYearOptional();
 
-        if (!isYearOptional) {
+        if (!isYearOptional && !TextUtils.isEmpty(oldValue)) {
             final ParsePosition position = new ParsePosition(0);
             final Date date2 = kind.dateFormatWithoutYear.parse(oldValue, position);