LU-17402 kernel: update dotdot patch path for RHEL 8.10

LU-17402 kernel: update dotdot patch path for RHEL 8.10

After commit 0536b2a landed, the patch path for
ext4-hash-indexed-dir-dotdot-update.patch was
changed from ubuntu18/ to rhel8.7/.

Test-Parameters: trivial fstype=ldiskfs mdtcount=4 mdscount=2 \
  clientdistro=el8.10 serverdistro=el8.10 testlist=sanity

Test-Parameters: optional clientdistro=el8.10 serverdistro=el8.10 \
  testgroup=full-part-1

Test-Parameters: optional clientdistro=el8.10 serverdistro=el8.10 \
  testgroup=full-part-2

Test-Parameters: optional clientdistro=el8.10 serverdistro=el8.10 \
  testgroup=full-part-3

Change-Id: I323fe06cfd125ad57959782bb33a2af81b705788
Fixes: 0536b2a ("LU-17711 osd-ldiskfs: do not delete dotdot during rename")
Signed-off-by: Jian Yu <yujian@whamcloud.com>