Declare ConfigConstants and GitProtocolConstants final

This avoids that we have to suppress API errors whenever we add a new
constant in a minor release. This change affects implementors only which
is ok to do in a minor release following OSGi semantic versioning rules.

Change-Id: Iece841886fbe00f1ba567c5ff68093c542ba265e
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit/.settings/.api_filters

@@ -1,5 +1,12 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <component id="org.eclipse.jgit" version="2">
+    <resource path="src/org/eclipse/jgit/lib/ConfigConstants.java" type="org.eclipse.jgit.lib.ConfigConstants">
+        <filter id="337768515">
+            <message_arguments>
+                <message_argument value="org.eclipse.jgit.lib.ConfigConstants"/>
+            </message_arguments>
+        </filter>
+    </resource>
     <resource path="src/org/eclipse/jgit/lib/ObjectIdSerializer.java" type="org.eclipse.jgit.lib.ObjectIdSerializer">
         <filter id="1141899266">
             <message_arguments>
@@ -16,4 +23,11 @@
             </message_arguments>
         </filter>
     </resource>
+    <resource path="src/org/eclipse/jgit/transport/GitProtocolConstants.java" type="org.eclipse.jgit.transport.GitProtocolConstants">
+        <filter id="337768515">
+            <message_arguments>
+                <message_argument value="org.eclipse.jgit.transport.GitProtocolConstants"/>
+            </message_arguments>
+        </filter>
+    </resource>
 </component>

org.eclipse.jgit/src/org/eclipse/jgit/lib/ConfigConstants.java

@@ -49,7 +49,7 @@ package org.eclipse.jgit.lib;
  * configuration keys
  */
 @SuppressWarnings("nls")
-public class ConfigConstants {
+public final class ConfigConstants {
 	/** The "core" section */
 	public static final String CONFIG_CORE_SECTION = "core";
 

org.eclipse.jgit/src/org/eclipse/jgit/transport/GitProtocolConstants.java

@@ -50,7 +50,7 @@ package org.eclipse.jgit.transport;
  *
  * @since 3.2
  */
-public class GitProtocolConstants {
+public final class GitProtocolConstants {
 	/**
 	 * Include tags if we are also including the referenced objects.
 	 *