Use correct offset to get time from ntpserver

:Release Notes:
get offset value with "offset:" string

:Detailed Notes:
add -"d" option to request ntptimeoffset : sntp -d us.pool.ntp.org

This commit depends on https://g2g.palm.com/#/c/2801/
This commit should be merged with other commit, which adds sntp.

:Testing Performed:
Tested in TV and Desktop
$ luna-send -n 1 -f luna://com.palm.systemservice/time/getNTPTime '{}'

expected result:
{
    "subscribed": false,
    "returnValue": true,
    "utc": 1372746542 //utc time must have value, not 0
}

:QA Notes:

:Issues Addressed:
[GF-10551] getNTPTime() doesn't work

Open-webOS-DCO-1.0-Signed-off-by: Youngeun Kim <ye0607.kim@lge.com>

Change-Id: Ic5623080aa0510f118b905afaf34642b73357dbd
Reviewed-on: https://g2g.palm.com/3099
Reviewed-by: Youngeun Kim <ye0607.kim@lge.com>
Tested-by: Youngeun Kim <ye0607.kim@lge.com>
Reviewed-by: Build Verification
Reviewed-by: DongHeon Jang <dongheon.jang@lge.com>
Tested-by: DongHeon Jang <dongheon.jang@lge.com>
Reviewed-by: Roger Stringer <roger.stringer@lge.com>