Startup race condition on Trusty

[mikepurvis]

The present init script, used on Ubuntu/Debian, can fail if the controller comes up before the hci device is available (or is enabled by connmand). The script is presently a one-shot-and-die:

qtsixa/sixad/sixad

Line 18 in c2f4ed9

bt_device_check () {

I would suggest that this check be replaced by multiple-try approach, perhaps five tries separated by 1 second each. Alternatively, if Ubuntu Trusty could be supplied with an Upstart job which specifies the respawn argument.