When we move content which we define custom URL alias for and remove its former parent the content becomes inaccessible.

Steps to reproduce:
1. Create a folder "test".
2. Create a new Landing Page under "test" and name it "test-lp".
3. Create a new custom URL alias for "test-lp". Mark option "Place alias at the site root" as disabled.
4. Move "test-lp" under another location.
5. Remove "test".
6. Try to access "test-lp" in the BO.

Result:
You will be presented with the following error:

An exception has been thrown during the rendering of a template ("Argument 'id' has a bad state: Unable to load path data, the path ...'custom_url' is broken, alias id '65' not found. To fix all broken paths run the ezplatform:urls:regenerate-aliases command").

See stacktrace.png for further reference.