E3-1720: Change submodule reset to silence error message
The error messages
error: could not lock config file .git/modules/foo/config: No such file or directory
warning: Could not unset core.worktree setting in submodule \'foo\'
can be seen for all non-local mode wrappers (source code as git submodule).
This happens if doing a git submodule deinit
before a submodule has
been initialised. If a submodule has been initialised, but then is
deinitialised twice, the second error message shown above is still
displayed.
This fixes the above cases by instead doing a forced recursive deletion of the submodule directory.