Travis/MacOS does not support /sbin/ip, use ifconfig instead

.travis.yml

@@ -942,8 +942,9 @@ before_script:
   # Check some settings of the build server
   - uname -a
   - pwd
-  - ls -l
-  - /sbin/ip addr show
+  #- ls -l
+  - ifconfig
+  #- /sbin/ip addr show
   # Generate the build scripts with CMake
   - mkdir output
   - cd output