Catch error in case $destroy is called twice

This error can happen when using ui-router, as ui-router will manage
your application lifecycle incorrectly. See this issue for more
information:

https://github.com/angular-ui/ui-router/issues/881

I have not managed to create a reproducible test case for the bug, but the error message that this prevents is:

    Failed to execute 'removeChild' on 'Node': The node to be removed is not a child of this node.

I will provide a test case if possible.