LU-17465 nodemap: change squash default value to 65534

LU-17465 nodemap: change squash default value to 65534

Initially, default values for nodemap.squash_uid/gid/projid were set
to 99, to match user 'nobody'. But on newer systems, nobody has
changed to 65534 and 99 no longer exists.
It is safe to use 65534 in all cases, as even on older systems it
exists and corresponds to 'nfsnobody'.

Lustre-change: https://review.whamcloud.com/53802
Lustre-commit: d4927da410525db5f0524d618da47a17fe9c7835

Test-Parameters: testlist=sanity env=ONLY=432 serverversion=EXA5
Test-Parameters: testlist=sanity env=ONLY=432 clientversion=EXA5
Test-Parameters: testlist=sanity-quota env=ONLY=75 serverversion=EXA5
Test-Parameters: testlist=sanity-quota env=ONLY=75 clientversion=EXA5
Test-Parameters: testlist=sanity-selinux env=ONLY=21 serverversion=EXA5
Test-Parameters: testlist=sanity-selinux env=ONLY=21 clientversion=EXA5
Test-Parameters: testlist=sanity-sec env=ONLY="7 8 9 10 11 12 13 14 15 16 18 19 20 21 22 23 24 25 26 27 32 33 34 35 36 55 61 64" serverversion=EXA5
Test-Parameters: testlist=sanity-sec env=ONLY="7 8 9 10 11 12 13 14 15 16 18 19 20 21 22 23 24 25 26 27 32 33 34 35 36 55 61 64" clientversion=EXA5
Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: I2e20fda0fdc0d5bfdf964a890bfbd0b54b943cf4
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/53777
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>