Make class for managing vc_config_s instance

Make class for managing vc_config_s instance

- Requirement:
g_config_info is shared memory, so thread safe access for g_config_info
is needed.

- Contents:
This patch makes new class for accessing vc_config_s instance. Through
this patch, all other functions in this module can access configuration
property in a thread safe way using method of new class.
This new class will protect vc_config_s property using mutex, so the
class will assure to prevent race condition.

Change-Id: Ifdf2c37874f9dfe53cc6f645149ec28036f8c0d2
Signed-off-by: Suyeon Hwang <stom.hwang@samsung.com>