Fix coverity issue

Fix coverity issue

When comparing operands that containing sizeof operator, both are taken
as unsigned. Therefore if an operand was -1, which might be a value of
error return, it is interpreted as unsigned value such as 4294967295
when it is compared with another operand, sizeof value. Make both
operands be signed by casting sizeof value into glong.

Change-Id: I116c507f50ad93f7b699c2524868e3c72979c376
Signed-off-by: Youngjae Cho <y0.cho@samsung.com>