EX-6014 tests: Revert "EX-4093 tests: hot-pools don't recreate pools"

EX-6014 tests: Revert "EX-4093 tests: hot-pools don't recreate pools"

This reverts commit 116cbacc52d8 to resolve the hot-pools
regression test failures.

After running sub-test 1, the OST pools were destroyed by
the following stack_trap in create_pool():

  stack_trap "destroy_test_pools $fsname" EXIT

If the pools are not recreated in the successive sub-tests,
then they will fail. We have to revert commit 116cbacc52d8
before we find out a way to avoid triggering the stack_trap
between sub-tests.

Test-Parameters: trivial mdscount=2 mdtcount=4 \
testlist=parallel-scale-nfsv4,hot-pools

Fixes: 116cbacc52d8 ("EX-4093 tests: hot-pools don't recreate pools")
Change-Id: I464a1f9f380c55e70b78a0dd7e52723d5b0a298d
Signed-off-by: Jian Yu <yujian@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/48690
Reviewed-by: Alexandre Ioffe <aioffe@ddn.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>