Attempt readthedocs workaround

readthedocs alters docs/conf.py which in turn means python_scm detects a
version and incorrectly adjusts the version number. Here we try to work
around this problem.

We do this by renaming the docs/conf.py file and copying it back to
docs/conf.py when setup.py is invoked. This way, hopefully, scm won't
see the changes to docs/conf.py

References:
http://stackoverflow.com/questions/35811267/readthedocs-and-setuptools-scm-version-wrong/36386177
https://github.com/pypa/setuptools_scm/issues/84

.gitignore

 sshuttle/version.py
+docs/conf.py
 *.pyc
 *~
 *.8

setup.py

@@ -18,7 +18,12 @@
 # along with python-tldap  If not, see <http://www.gnu.org/licenses/>.
 
 from setuptools import setup, find_packages
+import shutil
 
+with open("./docs/conf.orig.py", "r") as src:
+    with open("./docs/conf.py", "w") as dst:
+        dst.write("# FILE COPIED FROM conf.orig.py; DO NOT CHANGE\n")
+        shutil.copyfileobj(src, dst)
 
 def version_scheme(version):
     from setuptools_scm.version import guess_next_dev_version