Grammar corrected/recognize acl flags

1). A minor grammar error was corrected in main() when the ENOENT
    case is handled.

2). In both files, the header and the C code, these options are now
     accepted as passed through by mount in util-linux-2.24 when it execs mount.zfs:

	acl
	noacl
	posixacl

Apologies to all since I''m an old guy and though very familiar with CVS and other legacy SCM tools, this new-fangled GIT world is a steep learning curve for me so I hope I didn't break anything with the fork and pull process after following the Bootcamp/fork-a-repo tutorial. That tutorial only alludes to committing without an explicit example, so the prior pull request was wrong.