testing: assure we pass SSH agent

ssbarnea · ssbarnea · commit 639600a00881 · 2019-08-14T15:58:52.000+01:00
Prevents failure to run tests when local ssh key is encrypted.
diff --git a/tox.ini b/tox.ini
@@ -43,8 +43,9 @@ setenv =
     # but it validates that it accepts extra params.
     MOLECULE_OPTS=--destroy always
 passenv =
-    TWINE_*
     DOCKER_*
+    TWINE_*
+    SSH_AUTH_SOCK
 whitelist_externals =
     bash
     twine
