staging: lustre: remove initialisation of static variable

Fix the following checkpatch.pl error:

ERROR: do not initialise statics to 0 or NULL
+static int       libcfs_nidstring_idx = 0;

Signed-off-by: Teodora Baluta <teobaluta@gmail.com>
Reviewed-by: Lisa Nguyen <lisa@xenapiadmin.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>