block/011: recover test target NVME device capacity

block/011: recover test target NVME device capacity

The test case runs fio while disabling and enabling PCI device of the
test target block device. When the block device is a NVME PCI device,
the test triggers NVME controller reset. When an error happens during
the reset, NVME PCI driver marks zero capacity for the device. This
zero capacity device causes failures of the following test cases.

To avoid the failures by zero device capacity, check the capacity at the
test end. If it is zero, remove the device and rescan PCI bus to detect
the device again, and regain the correct capacity.

Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>