build.sh: Show all timestamps in UTC (v3.3.28)

:Release Notes:
The time format ends with "Z" as "Zulu" so use -u as "UTC".

:Detailed Notes:

:Testing Performed:
Only build tested.

:QA Notes:
No change to image.

:Issues Addressed:
[ES-1095] human-readable timestamps in build logs imply "Zulu" time but
          are actually local

Open-webOS-DCO-1.0-Signed-off-by: Martin Jansa <martin.jansa@lge.com>
Change-Id: I93774e23ab7204e0459c87c014304747312dca81
Reviewed-on: https://g2g.palm.com/6305
Reviewed-by: DCO Verification
Reviewed-by: Martin Jansa <Martin.Jansa@lge.com>
Tested-by: Martin Jansa <Martin.Jansa@lge.com>
Reviewed-by: Susan Montooth <susan.montooth@lge.com>

Author: shr-project

scripts/build.sh

@@ -18,7 +18,7 @@
 #set -x
 
 # Some constants
-SCRIPT_VERSION="3.3.26"
+SCRIPT_VERSION="3.3.28"
 SCRIPT_NAME=`basename $0`
 AUTHORITATIVE_OFFICIAL_BUILD_SITE="svl"
 
@@ -43,7 +43,7 @@ BUILD_BUILDHISTORY_BRANCH=
 # and form paths based on that
 CALLDIR=${PWD}
 
-BUILD_TIMESTAMP_START=`date +%s`
+BUILD_TIMESTAMP_START=`date -u +%s`
 BUILD_TIMESTAMP_OLD=$BUILD_TIMESTAMP_START
 
 TIME_STR="TIME: %e %S %U %P %c %w %R %F %M %x %C"
@@ -69,8 +69,8 @@ mkdir -p "${ARTIFACTS}"
 BUILD_TIME_LOG=${BUILD_TOPDIR}/time.txt
 
 function print_timestamp {
-  BUILD_TIMESTAMP=`date +%s`
-  BUILD_TIMESTAMPH=`date +%Y%m%dT%TZ`
+  BUILD_TIMESTAMP=`date -u +%s`
+  BUILD_TIMESTAMPH=`date -u +%Y%m%dT%TZ`
 
   local BUILD_TIMEDIFF=`expr ${BUILD_TIMESTAMP} - ${BUILD_TIMESTAMP_OLD}`
   local BUILD_TIMEDIFF_START=`expr ${BUILD_TIMESTAMP} - ${BUILD_TIMESTAMP_START}`