restore check-manifst functionality

scripts/check-manifest.py

@@ -18,4 +18,3 @@ if os.path.isdir('.git'):
 else:
     print('No .git directory found, skipping checking the manifest file')
     sys.exit(0)
-

tox.ini

@@ -47,6 +47,8 @@ commands=
 
 [testenv:linting]
 basepython = python2.7
+setenv = # needed to keep check-manifest working
+    SETUPTOOLS_SCM_PRETEND_VERSION=0.0.1
 deps =
     flake8
     # pygments required by rst-lint