Fix absolute adb path in Mac and Linux
Fix absolute adb path in Mac and Linux

Code was intended to search an absolute path (/opt/blah) but the first separation character isn't automatically added by os.join
mwasilew/AndroidViewClient,mwasilew/AndroidViewClient,dtmilano/AndroidViewClient,dtmilano/AndroidViewClient,mwasilew/AndroidViewClient,dtmilano/AndroidViewClient