Formalise Citadel client for Linux.

It now resides in host/linux and does not depend on the driver from
core/nugget/util/poker.

Change-Id: I555631bcf659e31f647a4f12d32c10883b10412f
diff --git a/libnos_datagram/WORKSPACE b/libnos_datagram/WORKSPACE
new file mode 100644
index 0000000..3d515e2
--- /dev/null
+++ b/libnos_datagram/WORKSPACE
@@ -0,0 +1 @@
+workspace(name = "nugget_host_generic_libnos_datagram")