[PATCH AUTOSEL for 3.18 022/101] usb: usbip tool: Check the return of get_nports()

From: Yuyang Du [ Upstream commit c3509715fc9484a48b69a9f0196b728c960840c9 ] If we get nonpositive number of ports, there is no sense to continue, then fail gracefully. In addition, the commit 0775a9cbc694e8c72 ("usbip: vhci extension: modifications to vhci driver")

[PATCH AUTOSEL for 3.18 022/101] usb: usbip tool: Check the return of get_nports()

From: Yuyang Du [ Upstream commit c3509715fc9484a48b69a9f0196b728c960840c9 ] If we get nonpositive number of ports, there is no sense to continue, then fail gracefully. In addition, the commit 0775a9cbc694e8c72 ("usbip: vhci extension: modifications to vhci driver") introduced configurable