tools/usbip: fixes potential (minor) "buffer overflow" (detected on recent gcc with -Werror)

Fixes following build error:
vhci_driver.c: In function 'refresh_imported_device_list':
vhci_driver.c:118:37: error: 'snprintf' output may be truncated before
	the last format character [-Werror=format-truncation=]
    snprintf(status, sizeof(status), "status.%d", i);
                                     ^~~~~~~~~~~
vhci_driver.c:118:4: note: 'snprintf' output between 9 and 18 bytes into
	a destination of size 17
    snprintf(status, sizeof(status), "status.%d", i);
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors

Signed-off-by: Julien BOIBESSOT <julien.boibessot@armadeus.com>
Acked-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>