manager: Don't return true when kernel didn't accept new strings or descriptors
manager: Don't return true when kernel didn't accept new strings or descriptors

Change-Id: I4677031cbe40e173084fbe74c34d79119062b95b
Signed-off-by: Karol Lewandowski <8fb8916c55d06d2ab80c72f8c4561ece4e86f62e@samsung.com>

gadgetd/gadgetd,gadgetd/gadgetd,gadgetd/gadgetd