util: avoid considering dpkg temporary files relevant for anything

https://bugs.freedesktop.org/show_bug.cgi?id=82453

src/shared/util.c

@@ -1422,6 +1422,7 @@ _pure_ static bool ignore_file_allow_backup(const char *filename) {
                 endswith(filename, ".rpmorig") ||
                 endswith(filename, ".dpkg-old") ||
                 endswith(filename, ".dpkg-new") ||
+                endswith(filename, ".dpkg-tmp") ||
                 endswith(filename, ".swp");
 }