MAC/do: Tests: Declare required programs closer to use

Reviewed by:    bapt
MFC after:      3 days
Sponsored by:   The FreeBSD Foundation
Pull Request:   https://ron-dev.freebsd.org/FreeBSD/src/pulls/38

tests/sys/mac/do/Makefile

@@ -9,6 +9,5 @@ ${PACKAGE}FILES+=	common.sh
 TEST_METADATA+=	execenv="jail"
 TEST_METADATA+=	required_kmods="mac_do"
 TEST_METADATA+=	required_user="root"
-TEST_METADATA+=	required_programs="sysctl"
 
 .include <bsd.test.mk>

tests/sys/mac/do/common.sh

@@ -69,5 +69,7 @@ sysctl_set_and_check_fails_rules()
     sysctl_set_and_check_rules_common sysctl_set_and_check_fails "$value"
 }
 
+atf_require_prog sysctl
+
 # Do not pollute kernel logs with parse errors
 sysctl $PPE_KNOB=0 >/dev/null 2>&1