Fix issue #2: Loop forever bug when deleting new (*,G) sourceless routes

- Avoid looping forever if no match.
- Avoid useless general case (not INADDR_ANY) route removal at the end.

Signed-off-by: Jean-Baptiste Maillet <jean-baptiste.maillet@parrot.com>
Signed-off-by: Joachim Nilsson <troglobit@gmail.com>
Simplify mroute4_del() and reduce indentation depth

This is a refactoring followup to 04dd45d which simplifies the
code a bit and reduces the indentation depth.  This makes the
code easier to read and follow and hopefully less error prone
for future changes.

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>
Update and correct ChangeLog