Fix JavaDoc

Author: mpv1989

src/main/java/com/arangodb/ArangoCollection.java

@@ -826,6 +826,7 @@ public void drop() throws ArangoDBException {
 	 * @param isSystem
 	 *            Whether or not the collection to drop is a system collection. This parameter must be set to true in
 	 *            order to drop a system collection.
+	 * @since ArangoDB 3.1.0
 	 * @throws ArangoDBException
 	 */
 	public void drop(final boolean isSystem) throws ArangoDBException {

src/main/java/com/arangodb/ArangoDB.java

@@ -836,6 +836,7 @@ public LogEntity getLogs(final LogOptions options) throws ArangoDBException {
 	 * Returns the server's current loglevel settings.
 	 * 
 	 * @return the server's current loglevel settings
+	 * @since ArangoDB 3.1.0
 	 * @throws ArangoDBException
 	 */
 	public LogLevelEntity getLogLevel() throws ArangoDBException {
@@ -848,6 +849,7 @@ public LogLevelEntity getLogLevel() throws ArangoDBException {
 	 * @param entity
 	 *            loglevel settings
 	 * @return the server's current loglevel settings
+	 * @since ArangoDB 3.1.0
 	 * @throws ArangoDBException
 	 */
 	public LogLevelEntity setLogLevel(final LogLevelEntity entity) throws ArangoDBException {