Fix warnings in ObjectFilter

- add missing tags in JavaDoc of ObjectFilter.include()
- remove unnecessary import

Change-Id: I24b9dcc49f66380f77345d704df70c05f7f74db8
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit/src/org/eclipse/jgit/revwalk/filter/ObjectFilter.java

 
 import org.eclipse.jgit.errors.IncorrectObjectTypeException;
 import org.eclipse.jgit.errors.MissingObjectException;
-import org.eclipse.jgit.errors.StopWalkException;
 import org.eclipse.jgit.lib.AnyObjectId;
 import org.eclipse.jgit.revwalk.ObjectWalk;
 
 	 * Determine if the named object should be included in the walk.
 	 *
 	 * @param walker
-	 *	      the active walker this filter is being invoked from within.
+	 *            the active walker this filter is being invoked from within.
 	 * @param objid
-	 *	      the object currently being tested.
+	 *            the object currently being tested.
+	 * @return {@code true} if the named object should be included in the walk.
+	 * @throws MissingObjectException
+	 *             an object the filter needed to consult to determine its
+	 *             answer was missing
+	 * @throws IncorrectObjectTypeException
+	 *             an object the filter needed to consult to determine its
+	 *             answer was of the wrong type
 	 * @throws IOException
-	 *	      an object the filter needed to consult to determine its answer
-	 *	      was missing, of the wrong type, or could not be read.
+	 *             an object the filter needed to consult to determine its
+	 *             answer could not be read.
 	 */
 	public abstract boolean include(ObjectWalk walker, AnyObjectId objid)
 			throws MissingObjectException, IncorrectObjectTypeException,