Remove osconf conditionals for linux24

Remove osconf conditionals for linux24

They are no longer triggerable now that linux 2.4 is desupported,
so make the code easier to read.

Change-Id: I77b48d30db66b635cfdc06e977f9884dd2825713
Reviewed-on: http://gerrit.openafs.org/11800
Reviewed-by: Perry Ruiter <pruiter@sinenomine.net>
Reviewed-by: Chas Williams <3chas3@gmail.com>
Reviewed-by: Daria Brashear <shadow@your-file-system.com>
Tested-by: Daria Brashear <shadow@your-file-system.com>