Fix ifconfig parsing in onos-setup-karaf

ifconfig output in CentOS7 is different from Ubuntu.
This one should work with OS X, Ubuntu and CentOS.

Change-Id: I2ec43db5af6f90b87b4def1a7654e4c8ad0bd253

@@ -17,9 +17,7 @@ export STAGE=$(dirname $KARAF_ROOT)
 # Validates the specified IP regular expression against existing adapters.
 # Excludes local-loopback.
 function validateIp {
-    [ $(uname) = "Darwin" ] && \
-        ifconfig | grep 'inet ' | cut -d\  -f2 | grep -v "127\.0\.0\.1" | grep $1 || \
-        ifconfig | grep 'inet addr:' | cut -d: -f2 | cut -d\  -f1 | grep -v "127\.0\.0\.1" | grep $1
+    ifconfig | awk '{ print $2}' | grep -E -o "([0-9]{1,3}[\.]){3}[0-9]{1,3}" | grep -v "127\.0\.0\.1" | grep $1
 }
 
 # Clean the previous Karaf directory if requested and if it exists.