LU-13440 utils: fix handling of lsa_stripe_off = -1

LU-13440 utils: fix handling of lsa_stripe_off = -1

Use LMV_OFFSET_DEFAULT instead of "-1" for parsing lfs_setdirstripe()
since parse_targets() will return "(__u32)-1" to the caller for the
stripe index, but lsa_stripe_off is a signed long long so it is
interpreted as 4294967295.  This causes the parsing to fail when
"lfs setdirstripe -i -1 --max-inherit-rr 1" is used.

Update sanity test_413a/413c to also specify "-i -1" to verify this.

Fixes: f167f78e3bfd ("LU-13440 lmv: add default LMV inherit depth")
Test-Parameters: trivial
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: Ic934f859173155b1b2df56fcd315c8da633ebbe5