refactor(ngInclude): remove scope attribute

The purpose of allowing the scope to be specified was to enable the $route service to work
together with ngInclude. However the functionality of creating scopes was in the recent past
moved from the $route service to the ngView directive, so currently there is no valid use case
for specifying the scope for ngInclude. In fact, allowing the scope to be defined can under
certain circumstances lead to memory leaks.

Breaks ngInclude does not have scope attribute anymore.