Fix API warnings for the new CommitGraph

Mark the internal package as internal, visible only to the test bundle.
Add an API filter for CoreConfig.DEFAULT_COMMIT_GRAPH_ENABLE.

Change-Id: Ib62a93b873c93daf638b6c57e62fd267e16801bb
Signed-off-by: Thomas Wolf <twolf@apache.org>
diff --git a/org.eclipse.jgit/.settings/.api_filters b/org.eclipse.jgit/.settings/.api_filters
new file mode 100644
index 0000000..ae801e2
--- /dev/null
+++ b/org.eclipse.jgit/.settings/.api_filters
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<component id="org.eclipse.jgit" version="2">
+    <resource path="src/org/eclipse/jgit/lib/CoreConfig.java" type="org.eclipse.jgit.lib.CoreConfig">
+        <filter id="336658481">
+            <message_arguments>
+                <message_argument value="org.eclipse.jgit.lib.CoreConfig"/>
+                <message_argument value="DEFAULT_COMMIT_GRAPH_ENABLE"/>
+            </message_arguments>
+        </filter>
+    </resource>
+</component>
diff --git a/org.eclipse.jgit/META-INF/MANIFEST.MF b/org.eclipse.jgit/META-INF/MANIFEST.MF
index b8afcec..453a716 100644
--- a/org.eclipse.jgit/META-INF/MANIFEST.MF
+++ b/org.eclipse.jgit/META-INF/MANIFEST.MF
@@ -81,7 +81,8 @@
   x-friends:="org.eclipse.jgit.test",
  org.eclipse.jgit.internal.revwalk;version="6.5.0";
   x-friends:="org.eclipse.jgit.test",
- org.eclipse.jgit.internal.storage.commitgraph;version="6.5.0",
+ org.eclipse.jgit.internal.storage.commitgraph;version="6.5.0";
+  x-friends:="org.eclipse.jgit.test",
  org.eclipse.jgit.internal.storage.dfs;version="6.5.0";
   x-friends:="org.eclipse.jgit.test,
    org.eclipse.jgit.http.server,