Fixed error log formating

src/rebar_log.erl

@@ -57,7 +57,7 @@ set_level(Level) ->
 
 log(Level = error, Str, Args) ->
     {ok, LogState} = application:get_env(rebar, log),
-    ec_cmd_log:Level(LogState, cf:format("~!^~s~n", [Str]), Args);
+    ec_cmd_log:Level(LogState, lists:flatten(cf:format("~!^~s~n", [Str])), Args);
 log(Level, Str, Args) ->
     {ok, LogState} = application:get_env(rebar, log),
     ec_cmd_log:Level(LogState, Str++"~n", Args).