Update rebar (should be correct this time)

core/deps.mk

@@ -163,7 +163,7 @@ define dep_autopatch_fetch_rebar
 	if [ ! -d $(ERLANG_MK_TMP)/rebar ]; then \
 		git clone -q -n -- https://github.com/rebar/rebar $(ERLANG_MK_TMP)/rebar; \
 		cd $(ERLANG_MK_TMP)/rebar; \
-		git checkout -q 791db716b5a3a7671e0b351f95ddf24b848ee173; \
+		git checkout -q 576e12171ab8d69b048b827b92aa65d067deea01; \
 		$(MAKE); \
 		cd -; \
 	fi
@@ -180,6 +180,7 @@ endef
 define dep_autopatch_rebar.erl
 	application:load(rebar),
 	application:set_env(rebar, log_level, debug),
+	rmemo:start(),
 	Conf1 = case file:consult("$(call core_native_path,$(DEPS_DIR)/$1/rebar.config)") of
 		{ok, Conf0} -> Conf0;
 		_ -> []