x11-base/xcb-proto: Add runtime blocker for x11-proto/xcb-proto

x11-proto/xcb-proto was moved to x11-base. Upstream has already moved
passed the need for this.

BUG=chromium:1121686
TEST=./update_chroot

Change-Id: Iefdb414d4d208f896791aa41902e85602050283a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/portage-stable/+/2376586
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: Allen Webb <allenwebb@google.com>
diff --git a/x11-base/xcb-proto/xcb-proto-1.14-r1.ebuild b/x11-base/xcb-proto/xcb-proto-1.14-r1.ebuild
index b352396..e2e5236 100644
--- a/x11-base/xcb-proto/xcb-proto-1.14-r1.ebuild
+++ b/x11-base/xcb-proto/xcb-proto-1.14-r1.ebuild
@@ -22,6 +22,7 @@
 DEPEND=""
 RDEPEND="
 	${PYTHON_DEPS}
+	!x11-proto/xcb-proto
 "
 BDEPEND="
 	${PYTHON_DEPS}