Suppress API error for new constant Ref.UNDEFINED_UPDATE_INDEX

Change-Id: If8f7c9cc4b78ce2de29b0d93f2b98c2d0dd1eb3d
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit/.settings/.api_filters

@@ -1,5 +1,13 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <component id="org.eclipse.jgit" version="2">
+    <resource path="src/org/eclipse/jgit/lib/Ref.java" type="org.eclipse.jgit.lib.Ref">
+        <filter id="403767336">
+            <message_arguments>
+                <message_argument value="org.eclipse.jgit.lib.Ref"/>
+                <message_argument value="UNDEFINED_UPDATE_INDEX"/>
+            </message_arguments>
+        </filter>
+    </resource>
     <resource path="src/org/eclipse/jgit/transport/Transport.java" type="org.eclipse.jgit.transport.Transport">
         <filter comment="Marked as final since overriding a deprecated stub is likely a mistake" id="421654647">
             <message_arguments>