dev-python/pytest-xdist: Integrate Laurent Bachelier's work

This is what I get for not searching for existing ebuilds before
starting from scratch ;).

diff --git a/dev-python/pytest-xdist b/dev-python/pytest-xdist
index 4104df27428b72f5aad5e0db682bf8fed7b8ee62..ea04814278daa576c9a1850bdbfe4b7fdcbe7c42 160000 (submodule)
--- a/dev-python/pytest-xdist
+++ b/dev-python/pytest-xdist
@@ -1 +1 @@
-Subproject commit 4104df27428b72f5aad5e0db682bf8fed7b8ee62
+Subproject commit ea04814278daa576c9a1850bdbfe4b7fdcbe7c42