audit(4) tests: require /etc/rc.d/auditd

These tests should be skipped if /etc/rc.d/auditd is missing, which could be
the case if world was built with WITHOUT_AUDIT set.  Also, one test case
requires /etc/rc.d/accounting.

Submitted by:	ngie
MFC after:	2 weeks
Pull Request:	https://github.com/freebsd/freebsd/pull/240

tests/sys/audit/Makefile

@@ -49,6 +49,7 @@ SRCS.miscellaneous+=		utils.c
 TEST_METADATA+= timeout="30"
 TEST_METADATA+= required_user="root"
 TEST_METADATA+= is_exclusive="true"
+TEST_METADATA+=	required_files="/etc/rc.d/auditd"
 
 WARNS?=	6
 

tests/sys/audit/administrative.c

@@ -377,6 +377,8 @@ ATF_TC_HEAD(acct_success, tc)
 {
 	atf_tc_set_md_var(tc, "descr", "Tests the audit of a successful "
 					"acct(2) call");
+	atf_tc_set_md_var(tc, "require.files",
+	    "/etc/rc.d/accounting /etc/rc.d/auditd");
 }
 
 ATF_TC_BODY(acct_success, tc)