vav: Don't reject individually quoted arguments

Cli command '"help" "help"' was wrongly rejected with error
message: "Missing separator between arguments"

bin/varnishtest/tests/b00008.vtc

@@ -49,3 +49,5 @@ varnish v1 -cliexpect 60 "param.show first_byte_timeout"
 varnish v1 -cliok "param.set cli_limit 128"
 
 varnish v1 -clierr 201 "param.show"
+
+varnish v1 -cliok "\"help\" \"help\""

lib/libvarnish/vav.c

@@ -192,7 +192,7 @@ VAV_ParseTxt(const char *b, const char *e, int *argc, int flag)
 			b++;
 			continue;
 		}
-		if (sep != NULL && *sep == '"' && *b == '"') {
+		if (sep != NULL && *sep == '"' && *b == '"' && (b - sep) < 2) {
 			argv[0] = err_missing_separator;
 			return (argv);
 		}
@@ -401,6 +401,7 @@ static const struct test_case *tests[] = {
 	TEST_PASS(    N, "foo\"bar", "foo\"bar"),
 	TEST_FAIL(0    , "foo\"bar", invalid_quote),
 	TEST_FAIL(0    , "foo\"bar", invalid_quote),
+	TEST_PASS(0    , "\"foo\" \"bar\"", "foo", "bar"),
 	TEST_PASS(    N, "\"foo\"\"bar\"", "\"foo\"\"bar\""),
 	TEST_FAIL(0    , "\"foo\"\"bar\"", missing_separator),
 	NULL