JAVA-896: Adding @SInCE Javadoc annotation to new public classes.

Author: jyemin

src/main/com/mongodb/MongoCursorNotFoundException.java

@@ -18,6 +18,8 @@
 
 /**
  * Subclass of {@link MongoException} representing a cursor-not-found exception.
+ *
+ * @since 2.12
  */
 public class MongoCursorNotFoundException extends MongoException {
 

src/main/com/mongodb/MongoSocketException.java

@@ -19,7 +19,9 @@
 import java.io.IOException;
 
 /**
- * Subclass of {@link MongoException} representing a network-related exception
+ * Subclass of {@link MongoException} representing a network-related exception.
+ *
+ * @since 2.12
  */
 public class MongoSocketException extends MongoException {