ASACORE-812: Enable switching to an unprivileged user after starting alljoyn-daemon

Also, default to the configuration to switch to user 'nobody'.

Change-Id: I28c835b7528d1c4138d684ad912bb31178332023
Signed-off-by: Steve Kinneberg <stevek@qce.qualcomm.com>
Merge "ASACORE-812: Enable switching to an unprivileged user after starting alljoyn-daemon"