[Bluetooth] Auto choose bluetooth type depend on which library availability.

Current bluetooth.gyp break desktop build because bluetooth% is hard
coded as tizen_capi.

Script identify_bluetooth_type.sh is added to return correct
bluetooth string depend on the exsit of pkgconfig(capi-network-bluetooth)
and version of pkgconfig(bluez).

BUG=None
Merge pull request #425 from halton/bt_type

[Bluetooth] Choose bluetooth depend on system avilable.