Fixed string-handling bugs for |csdk_security| module

Fixed string-handling bugs for |csdk_security| module

this change is for fixing string-handling bugs on |csdk_security|.
|OICSstr-xxx| APIs have |destSize| as its second parameter for
preventing buffer-overflow, but it makes the application crash,
mis-inputting |srcSize| as its second.

[patch #1] initial commit
[patch #2] fixed bugs related to get destSize

Change-Id: I4874b17fa71c13741226cb8650cfa4d53741b182
Signed-off-by: Kyungsun Cho <goodsun.cho@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/7635
Reviewed-by: Randeep Singh <randeep.s@samsung.com>
Tested-by: Randeep Singh <randeep.s@samsung.com>