Add new attribute to get gdbus connection from outside and etc.

1. gdbus connection will be always created when handle created,
but, sometimes, g_bus_get_sync got crashed.
So, muse server will get gdbus connection once at start time,
module will use it without getting gdbus connection.
2. RM related code modified.

[Version] 0.10.85
[Profile] Common
[Issue Type] Update
[Dependency module] N/A
[Dependency commit] N/A
[Test] [M(T) - Boot=(OK), sdb=(OK), Home=(OK), Touch=(OK), Version=tizen-mobile_20161024.2]

Change-Id: Id680ffbbcdb6213026898d226be7853359f9624a
Signed-off-by: Jeongmo Yang <jm80.yang@samsung.com>