Fix config client type as a bit flat

There is case that the app uses both client and setting API. In current code, this kind of usage
can cause invalid blocking to fix configuration file. Because current config client type is only
store single mode in one process.

To solve this problem, this patch changes config client type to bit flag variable. By this change,
a process can store multiple client type, and this can avoid wrong behavior.

Change-Id: I66bdb64cff148da5a0cc3cc725842265534d4842
Signed-off-by: Suyeon Hwang <stom.hwang@samsung.com>