Fix pkg 'Too many open files' errors

[pyhalov]

…ease soft fd limit

24681766 pkg cli tools should use pkgdefs constants

[pyhalov]

@citrus-it Have you seen this issue? I mean cli.t_pkg_linked.TestPkgLinkedScale.test_li_scale failure with 'Too many open files'.
I see two modes of failure

1. pkg in parent image dies with 'pkg: An error was encountered while attempting to store information about the current operation in client history' (when ulimit -n is 65536). If we raise ulimit to 128000 (or unlimited) or apply 'Try to remove limit on number of open files completely' patch, this stage finishes fine.
2. pkgs in child images die with 'Failed 'metadata update' for child image (system:img184) at path: /tmp/ips.test.27843/0/image184/: [Errno 24] Too many open files'. So far not sure what to do with this failure.

And yes, I've seen the failure in real life when we have a system with ~ 100 zones and do pkg update -r.

[citrus-it]

No, but the test is skipped on our build VMs as they only have 8GiB of RAM..

Can you work around the failure with -C 50 or whatever to pkg update? If so, you might be interested in our patch that adds pkg set-property recursion-concurrency omniosorg/pkg5@b99764b

[pyhalov]

No, '-C x' doesn't help

[pyhalov]

BASELINE MISMATCH: The following results didn't match the baseline.
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cli.t_pkgdep.py TestPkgdepBasics.test_PEP_3149: fail
cli.t_pkgdep.py TestPkgdepBasics.test_bug_11805: error
cli.t_pkgdep.py TestPkgdepBasics.test_bug_13059: fail
cli.t_pkgdep.py TestPkgdepBasics.test_output: error
cli.t_pkgdep.py TestPkgdepBasics.test_python_combinations: error
cli.t_pkg_info.py TestPkgInfoBasics.test_ranked: fail
cli.t_pkg_linked.py TestPkgLinkedRecurse.test_recursive_variant: fail
----------------------------------------------------------------------

This heals cli.t_pkg_linked.py TestPkgLinkedScale.test_li_scale test.