BUG/MINOR: checks: Remove bad call to free() when an expect rule is parsed

When an error is found during the parsing of an expect rule (tcp or http),
everything is released at the same place, at the end of the function.

Partly fixes issue #600. No backport needed.

src/checks.c

@@ -4305,7 +4305,6 @@ static struct tcpcheck_rule *parse_tcpcheck_expect(char **args, int cur_arg, str
 		chk->expect.custom = NULL; /* Must be defined by the caller ! */
 		break;
 	case TCPCHK_EXPECT_UNDEF:
-		free(chk);
 		memprintf(errmsg, "pattern not found");
 		goto error;
 	}