Fix IM installation in NBI

Change-Id: I10287cdb30aac7496eb28b82a06027d196a26a5b
Signed-off-by: Felipe Vicens <felipe.vicens@atos.net>
diff --git a/tox.ini b/tox.ini
index 27bc184..5654da5 100644
--- a/tox.ini
+++ b/tox.ini
@@ -15,7 +15,7 @@
 
 [tox]
 envlist = py3
-toxworkdir={homedir}/.tox
+toxworkdir={toxinidir}/.tox
 
 [testenv]
 basepython = python3