Remove old/obsolete directories from .gitignore (#26680)

Having old/obsolete directories in .gitignore can be very confusing and
may get people spending needless hours trying to understand what is
going on.

This fixes #26650

.gitignore

@@ -77,9 +77,6 @@ packaging/release/ansible_release
 /test/integration/inventory.remote
 /test/integration/inventory.networking
 /test/integration/inventory.winrm
-# old submodule dirs
-lib/ansible/modules/core
-lib/ansible/modules/extras
 # python 'rope' stuff
 .ropeproject
 # local 'ack' config files