Fix security unittest regarding iotvticalendartest on 32 bit OS

Fix security unittest regarding iotvticalendartest on 32 bit OS

-issue : IsRequestWithinValidTimeTest.IsRequestWithinValidTimeValidPeriod1 is failed on 32 bit OS
-reason : On 32 bit OS, integer overflow occur in return of mktime due to Year 2038 problem,
        when Checking whether endDateTime is after startDateTime in iotvticalendar.c
-solution : Checking the period using tm structure members instead of mktime and difftime function.

-Patch#5 : Split long lines

Change-Id: I5bb14336573ee8b7d42dbbe4f3c45af44f937c3e
Signed-off-by: js126.lee <js126.lee@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/4765
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Andrii Shtompel <a.shtompel@samsung.com>
Reviewed-by: Dmitriy Zhuravlev <d.zhuravlev@samsung.com>