Fix fget_only_user() to return ENOTCAPABLE on a failed capsicum check
After eaad8d1303da500ed691bd774742a4555a05e729 four additional
capsicum-test tests started failing. It turns out this is because
fget_only_user() was returning EBADF on a failed capsicum check instead
of forwarding the return value of cap_check_inline() like
fget_unlocked_seq().
capsicum-test failures before this:
[ FAILED ] 7 tests, listed below: [ FAILED ] Capability.OperationsForked [ FAILED ] Capability.NoBypassDAC [ FAILED ] Pdfork.OtherUserForked [ FAILED ] PipePdfork.WildcardWait [ FAILED ] OpenatTest.WithFlag [ FAILED ] ForkedOpenatTest_WithFlagInCapabilityMode._ [ FAILED ] Select.LotsOFileDescriptorsForked
After:
[ FAILED ] 3 tests, listed below: [ FAILED ] Capability.NoBypassDAC [ FAILED ] Pdfork.OtherUserForked [ FAILED ] PipePdfork.WildcardWait
Reviewed By: mjg
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D28691