Remove linting test that is broken upstream.
Bug: https://bugs.gentoo.org/807205

--- piper-0.5.1/meson.build
+++ piper-0.5.1/meson.build
@@ -119,11 +119,3 @@
                configuration: config_piper_devel)
 
 meson.add_install_script('meson_install.sh')
-
-flake8 = find_program('flake8', required: false)
-if flake8.found()
-    test('flake8', flake8,
-         args: ['--ignore=E501,W504',
-                join_paths(meson.source_root(), 'piper'),
-                join_paths(meson.source_root(), 'piper.in')])
-endif