Edited connection flags for Linux

Using linux based systems with ofArduino, causes an incorrect initialization of serial port because of missing flags.

References:  
[http://forum.openframeworks.cc/t/einitialized-never-fired-with-ofarduino/15704](http://forum.openframeworks.cc/t/einitialized-never-fired-with-ofarduino/15704)  
[http://forum.openframeworks.cc/t/ofarduino-and-raspberry-pi/12443](http://forum.openframeworks.cc/t/ofarduino-and-raspberry-pi/12443)