cloud.clouds.nova: rm duplicate import

************* Module salt.cloud.clouds.nova
salt/cloud/clouds/nova.py:113: [W0404(reimported), ] Reimport 'salt.utils.cloud' (imported line 100)
Merge pull request #12784 from cvrebert/patch-1

cloud.clouds.nova: rm duplicate import
Indicate rbenv support in 'gem' module and states
use list comprehension instead of filter() to avoid pylint warning

************* Module salt.pillar.s3
salt/pillar/s3.py:247: [W0640(cell-var-from-loop), _refresh_buckets_cache_file.<lambda>] Cell variable saltenv defined in loop

More details: https://github.com/klen/pylama_pylint/blob/master/pylama_pylint/pylint/checkers/variables.py#L150
Documentation to fix #6300
Fix #12766

@basepi, I need to manually fix this in 2014.1, don't cherrypick
Merge pull request #12786 from hulu/s3-pylint

use list comprehension instead of filter() to avoid pylint warning
Merge pull request #12785 from dnd/add_rbenv_to_ruby_gem_docs

Indicate rbenv support in 'gem' module and states
Merge branch 'develop' into with-pylint-pragmas