Permit testing sans Valgrind

Only run the check_exec on Valgrind when present as the prefix to the
--valgrind-cmd argument. This lets us run the test suite without
Valgrind via:

    ./tests/runtests.py --valgrind-cmd ""

Signed-off-by: Alexander Scheel <[email protected]>
Reviewed-by: Robbie Harwood <[email protected]>
Merges: #243

Author: cipherboy

tests/runtests.py

@@ -52,6 +52,9 @@ def runtests_main(testfiles):
     for e in ["bash", "pkg-config", "zcat", "kinit", "krb5kdc", "kdb5_util",
              "kadmin.local", "kdb5_ldap_util", "slapd", "slapadd",
               "ldapmodify", "valgrind"]:
+        if e == "valgrind" and not args['valgrind_cmd'].startswith('valgrind'):
+            continue
+
         check_exec(e)
 
     testdir = args['path']