Start running dib-lint again

A recent change that didn't fail with hard-tabs made me realise we're
not running tox -e pep8 ... which means we're not running dib-lint
which should find this (and other things).

I couldn't pinpoint when this happened; maybe job config was never in
this repo.

Anyway, move the pylint and dib-lint/flake8 testing to the now
standard "linters" and update the linting job to
openstack-tox-linters.

It looks like pylint is very lightly used (came in with
I7e24d8348db3aef79e1395d12692199a1f80161a and we've never expanded any
testing).  Leave this alone for now, but probably it is not important
any more.

This revealed some issues; updated flake8
(Iaa19c36f8cab8482a01f764c588375db8e7d8be3) found some spacing issues
with keywords and an update to elrepo to match our standard bash
flags.

Change-Id: I45bf108c467f7c8190ca252e6c48450c2622aaf8

.zuul.d/project.yaml

@@ -9,7 +9,7 @@
       - tripleo-buildimage-jobs-centos-8
     check:
       jobs:
-        - openstack-tox-pylint
+        - openstack-tox-linters
         - tox-py36:
             nodeset:
               nodes:
@@ -55,7 +55,7 @@
         - dib-functests-arm64-rpm
     gate:
       jobs:
-        - openstack-tox-pylint
+        - openstack-tox-linters
         - tox-py36:
             nodeset:
               nodes:

diskimage_builder/block_device/tests/test_lvm.py

@@ -60,7 +60,7 @@ class TestLVM(tc.TestGraphGeneration):
                                LVMPlugin, bad_config, {}, {})
 
         bad_config = copy.deepcopy(lvm_config)
-        del(bad_config['lvs'][0]['size'])
+        del bad_config['lvs'][0]['size']
         self.assertRaisesRegex(BlockDeviceSetupException,
                                "Missing 'size' or 'extents' in lvs config",
                                LVMPlugin, bad_config, {}, {})

diskimage_builder/element_dependencies.py

@@ -178,7 +178,7 @@ def _expand_element_dependencies(user_elements, all_elements):
         raise MissingOSException("Please include an operating system element")
 
     out = final_elements - provided
-    return([all_elements[element] for element in out])
+    return [all_elements[element] for element in out]
 
 
 def _find_all_elements(paths=None):

diskimage_builder/elements/elrepo/pre-install.d/01-elrepo

@@ -4,7 +4,8 @@ if [ ${DIB_DEBUG_TRACE:-0} -gt 0 ]; then
     set -x
 fi
 
-set -euo pipefail
+set -eu
+set -o pipefail
 
 case "$DISTRO_NAME" in
     centos* | rhel* | rocky*)

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = pep8,pylint,py3
+envlist = pep8,linters,py3
 minversion = 3.18.0
 skipsdist = True
 ignore_basepython_conflict = True
@@ -18,14 +18,12 @@ passenv=
 deps = bindep
 commands = bindep test
 
-[testenv:pep8]
+[testenv:linters]
 commands =
+  pylint --rcfile pylint.cfg diskimage_builder
   flake8 {posargs}
   dib-lint
 
-[testenv:pylint]
-commands = pylint --rcfile pylint.cfg diskimage_builder
-
 [testenv:venv]
 commands = {posargs}