Add in a missing mtree entry for /usr/tests/usr.bin/grep
Convert TESTS_C to ATF_TESTS_C

Sponsored-by: EMC / Isilon Storage Division
Install the additional test mtree file

Sponsored-by: EMC / Isilon Storage Division
Merge branch 'atf' into isilon-atf
Merge branch 'isilon-atf' of https://github.com/yaneurabeya/freebsd into isilon-atf