ktrace/kdump give incorrect message on unlinkat() failure due to capabilities

[Ryan Stone]

I have written a short test program that runs unlinkat(2) in
capability mode and fails due to not having the write capabilities:

https://people.freebsd.org/~rstone/src/unlink.c

If I run the binary under ktrace and look at the kdump output, it
gives the following incorrect output:

43775 unlink   CALL  unlinkat(0x3,0x7fffffffe995,0)
43775 unlink   NAMI  "from.QAUlAA0"
43775 unlink   CAP   operation requires CAP_LOOKUP, descriptor holds CAP_LOOKUP
43775 unlink   RET   unlinkat -1 errno 93 Capabilities insufficient

The message should instead say that the operation requires
CAP_UNLINKAT.  Looking at sys/capsicum.h, I suspect that the problem
is related to the strange definition of CAP_UNLINKAT:

#define CAP_UNLINKAT (CAP_LOOKUP | 0x0000000010000000ULL)

I have observed the same problem with renameat(2) and
CAP_RENAMEAT_SOURCE and CAP_RENAMEAT_TARGET:

https://people.freebsd.org/~rstone/src/rename.c