external/connectivity: Check for null string before strcmp

The strcmp function with null string causes a crash. This occurs
when an entry is added to routing table that has a null interface.

Change-Id: I919975c8ab114000c1ae67a0a867e15f9934e21a
CRs-fixed: 253597
1 file changed
tree: a814309f6de9eab0b1a9f420c791facd5c382120
  1. cnd/
  2. include/
  3. reference-cne/
  4. stlport/