[FS#625] no default route written using proto=wwan

[LEDE Bugs]

A Project Manager has denied the request pending for the following task:

FS#625 - no default route written using proto=wwan
User who did this - Mathias Kresin (mkresin)

Reason for denial:
FS#626 was closed as duplicate of this one

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=625