test: drop inotify exclusions

Simplify how we run flake8 in static-code, add the inotify undefined
issues as builtins in favor of adding undefined exceptions in our
.flake8 configuration file.

.flake8

@@ -2,5 +2,13 @@
 ignore=
     # line break after binary operator
     W504
+builtins =
+    # inotify.py get pasted together with other files
+    Inotify,
+    IN_CREATE, IN_MOVED_TO,
+    IN_MOVED_FROM, IN_MOVE_SELF,
+    IN_DELETE, IN_DELETE_SELF,
+    IN_CLOSE_WRITE,
+    IN_IGNORED,
 
 max-line-length = 200

test/static-code

@@ -26,8 +26,7 @@ find_python_files() {
 
 test_flake8() {
     command -v flake8 >/dev/null || skip 'no flake8'
-    filter="(undefined name '(Inotify|IN_[A-Z_]+)')" # inotify.py get pasted together with other files
-    ! find_python_files | xargs -r -0 flake8 2>&1 | grep -Ev "${filter}"
+    find_python_files | xargs -r -0 flake8
 }
 
 test_pyvulture() {