Tar regression from 6.2 to 6.3 with --strip-components

[Tim Kientzle]

>> I've just noticed a regression in tar from 6.2 to 6.3:
>>
>> Running this on 6.2 produces no output:
>>
>> #!/bin/sh
>> mkdir -p a b output
>> touch a/file1 b/file2
>> tar cf test.tar a b
>> tar -x -C output --strip-components 1 -f test.tar
>>
>> On 6.3, it produces this output:
>>
>> : Invalid empty pathname
>> : Invalid empty pathname
>> tar: Error exit delayed from previous errors.

Please file this in a PR so I won't lose
track.  I don't have time to investigate this
right now, but I should be able to get to it
sometime next week.

Tim