add bad_download error

src/rebar_fetch.erl

@@ -65,6 +65,8 @@ needs_update(AppDir, Source, State) ->
             true
     end.
 
+format_error({bad_download, CachePath}) ->
+    io_lib:format("Download of package does not match md5sum from server: ~s", [CachePath]);
 format_error({failed_extract, CachePath}) ->
     io_lib:format("Failed to extract package: ~s", [CachePath]);
 format_error({bad_etag, Source}) ->

src/rebar_pkg_resource.erl

@@ -67,7 +67,7 @@ serve_from_download(TmpDir, CachePath, Package, ETag, Binary, State) ->
         ETag ->
             serve_from_cache(TmpDir, CachePath, Package, State);
         FileETag ->
-            ?DEBUG("Download ETag ~s doesn't match cached ETag ~s", [ETag, FileETag]),
+            ?DEBUG("Download ETag ~s doesn't match returned ETag ~s", [ETag, FileETag]),
             {bad_download, CachePath}
     end.