Remove no longer used API problem filter

Change-Id: I29e7af25bad5282c6b09e4688bdcf23e22a0648f
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit/.settings/.api_filters

@@ -1,14 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <component id="org.eclipse.jgit" version="2">
-    <resource path="src/org/eclipse/jgit/lib/RefDatabase.java" type="org.eclipse.jgit.lib.RefDatabase">
-        <filter id="1141899266">
-            <message_arguments>
-                <message_argument value="5.6"/>
-                <message_argument value="5.7"/>
-                <message_argument value="hasFastTipsWithSha1()"/>
-            </message_arguments>
-        </filter>
-    </resource>
     <resource path="src/org/eclipse/jgit/transport/ReceivePack.java" type="org.eclipse.jgit.transport.ReceivePack">
         <filter id="336658481">
             <message_arguments>