s4-common: use bluetooth.hciattach property and updated bt.sh

PatchSet 1: initial commit
PatchSet 2: re-add license
PatchSet 3: add to common-proprietary-files.txt

Change-Id: I565b2db94887854df1704b2f8c47236283241a19
Merge "s4-common: use bluetooth.hciattach property and updated bt.sh" into cm-10.2