contrib/opendht: update to 1.7.3rc3

Change-Id: I4844a739e3d03dd57588fafbfd06609da452cfd4
Reviewed-by: Philippe Gorley <philippe.gorley@savoirfairelinux.com>

contrib/src/opendht/SHA512SUMS

-0e0d01a2db622fc669e8794e791c0a63defcf7e6c9094b56f71e134428a39ab8d5646aa55d905d1ef4561a74c96c02bb3b37b6f78b1c6742c3e0f62d46220a7d  opendht-1.7.3rc2.tar.gz
+f6740412ed0c654fd26d45e9529904f4fa71747534adc0026310a0d2f32269bec62eb118c8d68b83c340549f310c56c584ce56d84f9d38b6b742947040e29929  opendht-1.7.3rc3.tar.gz

contrib/src/opendht/rules.mak

 # OPENDHT
-OPENDHT_VERSION := 1.7.3rc2
+OPENDHT_VERSION := 1.7.3rc3
 OPENDHT_URL := https://github.com/savoirfairelinux/opendht/archive/$(OPENDHT_VERSION).tar.gz
 
 PKGS += opendht