ls broken on some systems

names are not correctly displayed on some systems.

vef@z0250 ~ $ LD_PRELOAD=/lustre/miifs01/project/m2_zdvresearch/vef/gekkofs/build/src/client/libgkfs_intercept.so cp ~/.bashrc /tmp/mountdir/bashrc
vef@z0250 ~ $ LD_PRELOAD=/lustre/miifs01/project/m2_zdvresearch/vef/gekkofs/build/src/client/libgkfs_intercept.so ls -l /tmp/mountdir
ls: cannot access /tmp/mountdir/sbashrc: No such file or directory
total 0
-????????? ? ? ? ?            ? sbashrc

This is due to an incorrect alignment of member d_name in getdents().

Commit 15cee453 causes it.

This is partly a revert to previous functionality which was removed during code maintenance, but so that the modified linux_dirent struct is only used in gkfs_functions.cpp.