doc/rdm1: fix URL to poster abstract

doc/memos/rdm0001.md

@@ -321,7 +321,7 @@ www.gnu.org/philosophy/free-sw.en.html.](https://www.gnu.org/philosophy/free-sw.
 [3] [Emmanuel Baccelli, Oliver Hahm, Mesut Günes, Matthias Wählisch, Thomas C.
 Schmidt, "RIOT OS: Towards an OS for the Internet of Things," in Proceedings of
 the 32nd IEEE International Conference on Computer Communications (INFOCOM),
-Poster, p. 79–80, IEEE Press, April 2013.](https://www.riot-os.org/docs/riot-infocom2013-abstract.pdf) \
+Poster, p. 79–80, IEEE Press, April 2013.](https://www.riot-os.org/assets/pdfs/riot-infocom2013-abstract.pdf) \
 [4] [E. Baccelli, C. Gündogan, O. Hahm, P. Kietzmann, M. Lenders, H. Petersen,
 K. Schleiser, T.C. Schmidt, M. Wählisch: "RIOT: an Open Source Operating System
 for Low-end Embedded Devices in the IoT", IEEE Internet of Things Journal, Vol.