Whitelist the coverage command in tox.ini to avoid some warnings.

aerostitch · atodorov · commit 1bc6e6cc3916 · 2019-01-03T00:18:15.000+02:00
diff --git a/tox.ini b/tox.ini
@@ -41,6 +41,8 @@ setenv =
 whitelist_externals =
     django_not_installed: bash
     readme: bash
+    py{36}-django{111,20,-master}: coverage
+    py{35,36,37}-django21: coverage
     clean: find
     clean: rm
 
