MANIFEST.in: exclude .coafile (coala)

MANIFEST.in

@@ -1,5 +1,5 @@
 include README.rst AUTHORS LICENSE CHANGES.rst MANIFEST.in
-exclude .coveragerc .gitattributes .gitignore .travis.yml Vagrantfile
+exclude .coafile .coveragerc .gitattributes .gitignore .travis.yml Vagrantfile
 prune .travis
 prune .github
 graft src