Add bash completion for OSC

use openstackclient to generate bash completion script, and move
the file to the right location.

Change-Id: I96f2230cbba030e235161165d3b173c7af5e28fe
diff --git a/stack.sh b/stack.sh
index 585d1ce..37b4e28 100755
--- a/stack.sh
+++ b/stack.sh
@@ -1312,6 +1312,13 @@
 service_check
 
 
+# Bash completion
+# ===============
+
+# Prepare bash completion for OSC
+openstack complete | sudo tee /etc/bash_completion.d/osc.bash_completion > /dev/null
+
+
 # Fin
 # ===