start-stop-daemon: fix "both -x and -a" case: -a does override argv[0]

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

testsuite/start-stop-daemon.tests

@@ -21,4 +21,11 @@ testing "start-stop-daemon without -x and -a" \
 	"1\n" \
 	"" ""
 
+# Unfortunately, this does not actually check argv[0] correctness,
+# but at least it checks that pathname to exec() is correct
+testing "start-stop-daemon with both -x and -a" \
+	'start-stop-daemon -S -x /bin/false -a qwerty false 2>&1; echo $?' \
+	"1\n" \
+	"" ""
+
 exit $FAILCOUNT