Fix warning on 32-bit ARM: 2 << 31 overflows int

Thanks to GCC 6.1 for finding this.

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

conf.c

@@ -197,7 +197,7 @@ void conf_parse_rlimit(char *line)
 	} else {
 		const char *err = NULL;
 
-		new = strtonum(tok, 0, 2 << 31, &err);
+		new = strtonum(tok, 0, (long long)2 << 31, &err);
 		if (err)
 			goto fail;
 	}