Update hacking for Python3

The repo is Python 3 now, so update hacking to version 3.0 which
supports Python 3.

Fix problems found by updated hacking version.

Update local hacking checks for new flake8.

Remove hacking and friends from lower-constraints, they are not
needed in installations.

Change-Id: If787d610315be6c973b4335e047242c3aa3caf2a

lower-constraints.txt

@@ -30,13 +30,11 @@ eventlet==0.22.0
 extras==1.0.0
 fasteners==0.14.1
 fixtures==3.0.0
-flake8==2.5.5
 future==0.16.0
 futurist==1.6.0
 glance-store==0.26.1
 google-auth==1.4.1
 greenlet==0.4.13
-hacking==0.12.0
 heat-translator==2.0.0
 idna==2.6
 imagesize==1.0.0
@@ -92,7 +90,6 @@ paramiko==2.0.0
 Paste==2.0.2
 PasteDeploy==1.5.0
 pbr==2.0.0
-pep8==1.5.7
 pkg-resources==0.0.0
 prettytable==0.7.2
 psutil==5.4.3
@@ -100,7 +97,6 @@ pyasn1-modules==0.2.1
 pyasn1==0.4.2
 pycadf==2.7.0
 pycparser==2.18
-pyflakes==0.8.1
 Pygments==2.2.0
 pyinotify==0.9.6
 PyNaCl==1.2.1