interface: Disconnect interfaces properly

interface: Disconnect interfaces properly

Some interfaces can be connected automatically without host runs lthor
due to the characteristics of connection such as usb. So, even the
network interface is used for transmitting image, usb connection
thread may wait for handshake. Previously in this case, when flashing
via network is not completed successfully, usb cannot be
re-initialized since the previous usb connection is not closed
properly. Thus, this patch makes sure all interfaces are disconnected
when the flash-manager is terminated.

Change-Id: I019e75b0bb774c292a2d7c142c0d00c7942322e1
Signed-off-by: Dongwoo Lee <dwoo08.lee@samsung.com>