USBPcapCMD: Fix invalid free found by Coverity Scan.

CID #1147971: Copy-paste error
CID #1147990: Double free
USBPcapDriver: Explicitly initialize pdo_driverkey to NULL.

CID #1147988: Uninitialized pointer read
USBPcapCMD: Fix memory leak.

CID #1147981: Resource leak
USBPcapCMD: Fix memory leak.

CID #1147979: Resource leak