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.

Change lower-constraints to make pip resolver happy.

Add bindep.txt to provide dev libraries to build python modules.

Change-Id: I4edc2ebc7b29849901964279b5cc551944d830a9

bindep.txt

@@ -0,0 +1,9 @@
+# these are needed to compile Python dependencies from sources
+python-dev [platform:dpkg test]
+python3-all-dev [platform:dpkg test]
+python-devel [platform:rpm test]
+python3-devel [platform:rpm test]
+build-essential [platform:dpkg test]
+libffi-dev [platform:dpkg test]
+libffi-devel [platform:rpm test]
+

lower-constraints.txt

@@ -1,6 +1,7 @@
 appdirs==1.3.0
 Babel==2.3.4
 bcrypt==3.1.3
+cffi==1.1.0
 chardet==3.0.4
 coverage==4.0
 debtcollector==1.2.0

test-requirements.txt

@@ -3,11 +3,9 @@
 # process, which may cause wedges in the gate later.
 
 coverage!=4.4,>=4.0 # Apache-2.0
-flake8-import-order>=0.17.1 # LGPLv3
-hacking>=3.1.0,<4.0.0 # Apache-2.0
 stestr>=1.0.0 # Apache-2.0
 oslotest>=3.2.0 # Apache-2.0
-doc8>=0.6.0 # Apache-2.0
-pycodestyle>=2.0.0,<2.7.0 # MIT
-Pygments>=2.2.0 # BSD
+
+# doc requirements
+doc8>=0.6.0 # Apache-2.0
 

tox.ini

@@ -35,6 +35,12 @@ application-import-names = ironic_lib
 enable-extensions=H106,H203,H204,H205,H210,H904
 
 [testenv:pep8]
+deps =
+    flake8-import-order>=0.17.1 # LGPLv3
+    hacking>=3.1.0,<4.0.0 # Apache-2.0
+    pycodestyle>=2.0.0,<2.7.0 # MIT
+    Pygments>=2.2.0 # BSD
+    doc8>=0.6.0 # Apache 2.0
 commands =
     flake8 {posargs}
     doc8 README.rst doc/source --ignore D001