Problems with IP addressing that can be trigerred by using ifconfig

[atis.elsts]

Problem 1: losing connectivity due to incorrect routing table
To repeat:

• create interface alias with same IP address as some existing interface
  
• delete the alias interface or change its address
  
• now the old IP address cannot be pinged anymore, because the connected route has been deleted.
  

Problem 2: kernel panic due to incorrect routing table
To repeat:

• create interface alias with an IP address that has the same network part as some already existing address
  
• delete the interface alias
  
• try to ping the address that belonged to the removed alias
  
• kernel panic happens. The callstack shows find_route() function as the culprit.
  

Haiku version is R1/alpha2. I'm using the anyboot image with QEMU.

[axeld]

Problem 1 fixed in hrev37691, problem 2 in hrev37692.