nfsstat: Complete libxo transition.

[lwhsu]

usr.bin/nfsstat/nfsstat.c

86

Please avoid contiguous blank lines.

[yanhaowang]

Remove unnecessary space.

[des]

usr.bin/nfsstat/nfsstat.c

507–508

This should be xo_error().

[yanhaowang]

usr.bin/nfsstat/nfsstat.c

507–508

Maybe use xo_err(1, "usage: nfsstat [-cdemszW] [-w wait]\n"); to replace the fprintf and exit function?

[yanhaowang]

This comment was removed by yanhaowang.

[yanhaowang]

usr.bin/nfsstat/nfsstat.c

507–508

Ignore this, xo_err can't replace fprintf.

[yanhaowang]

• Use xo_error instead of fprintf.
• Decide using 1 and 0 instead of EXIT_FAILURE and EXIT_SUCESS.