Adjust a position of calling OnCreate() method of base class

Adjust a position of calling OnCreate() method of base class

To improve performance about returning the result to the caller process,
the AppCoreEflBase::OnCreate() method has to be invoked before calling the
app_create_cb() function. When calling the AppCoreEflBase::OnCreate() method,
the application core calls the aul_launch_init() function. In that time,
the application sends the app startup signal to AMD to notify that the
application is started. And then, AMD sends the result of the launch
request to the caller process.

Change-Id: I34be9040a8a7c89facedd62db62ad89dbf8ec2e6
Signed-off-by: Hwankyu Jhun <h.jhun@samsung.com>