IZkChildListener$handleChildChange javadoc is inconsistent and misleading

[sslavic]

https://github.com/sgroschupf/zkclient/blob/master/src/main/java/org/I0Itec/zkclient/IZkChildListener.java#L32 suggests that handleChildChange method is only

Called when the children of the given path changed.

while https://github.com/sgroschupf/zkclient/blob/master/src/main/java/org/I0Itec/zkclient/IZkChildListener.java#L37 suggests that it is also called when parent path is deleted in which case currentChilds will be null.