Fix lower-constraints with the new pip resolver

* Remove pep8 dependencies from test-requirements, they're not
needed there and are hard to constraint properly.

* Add cliff to l-c (same version we have on ironic)

Change-Id: I8e7582492276db2308217460af37f691fb99c0ce

lower-constraints.txt

@@ -5,6 +5,7 @@ bashate==0.5.1
 certifi==2018.1.18
 cffi==1.14.0
 chardet==3.0.4
+cliff==3.1.0
 coverage==4.0
 cryptography==2.3
 debtcollector==1.19.0

test-requirements.txt

@@ -1,15 +1,11 @@
 # The order of packages is significant, because pip processes them in the order
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
-hacking>=3.1.0,<4.0.0 # Apache-2.0
 coverage!=4.4,>=4.0 # Apache-2.0
 testtools>=2.2.0 # MIT
 oslotest>=3.2.0 # Apache-2.0
 stestr>=1.0.0 # Apache-2.0
-bashate>=0.5.1 # Apache-2.0
-flake8-import-order>=0.17.1 # LGPLv3
 bandit!=1.6.0,>=1.1.0,<2.0.0 # Apache-2.0
-pycodestyle>=2.0.0,<2.7.0 # MIT
 
 # Doc test requirements
 doc8>=0.6.0 # Apache-2.0

tox.ini

@@ -33,6 +33,12 @@ setenv =
 commands = stestr run {posargs}
 
 [testenv:pep8]
+deps=
+    hacking>=3.1.0,<4.0.0 # Apache-2.0
+    bashate>=0.5.1 # Apache-2.0
+    flake8-import-order>=0.17.1 # LGPLv3
+    pycodestyle>=2.0.0,<2.7.0 # MIT
+    doc8>=0.6.0 # Apache-2.0
 whitelist_externals = bash
 commands =
   flake8 {posargs:ironic_python_agent examples}