examples/local - vttablet-up.sh - use hostname -i only in travis build (fix3)

examples/local/vttablet-up.sh

@@ -14,7 +14,7 @@ grpc_port_base=16100
 mysql_port_base=33100
 hostname=''
 
-if [[ "$TRAVIS" == "true" ]]; then
+if [ "$TRAVIS" = true ]; then
   hostname=`hostname -i`
 fi