Drop redundant lib/oslo

It was kept for compatibility in renaming which was merged long ago[1],
and is no longer necessary.

[1] 3ed99c0b27

Depends-on: https://review.opendev.org/c/openstack/grenade/+/936095
Change-Id: I6a66359c19d0385beafb4c5e57b6ec3cd6d9cc54

clean.sh

@@ -40,7 +40,7 @@ source $TOP_DIR/lib/rpc_backend
 
 source $TOP_DIR/lib/tls
 
-source $TOP_DIR/lib/oslo
+source $TOP_DIR/lib/libraries
 source $TOP_DIR/lib/lvm
 source $TOP_DIR/lib/horizon
 source $TOP_DIR/lib/keystone

lib/libraries

@@ -1,6 +1,6 @@
 #!/bin/bash
 #
-# lib/oslo
+# lib/libraries
 #
 # Functions to install libraries from git
 #

lib/oslo

@@ -1,11 +0,0 @@
-#!/bin/bash
-#
-# lib/oslo
-#
-# Functions to install **Oslo** libraries from git
-#
-# We need this to handle the fact that projects would like to use
-# pre-released versions of oslo libraries.
-#
-# Included for compatibility with grenade, remove in Queens
-source $TOP_DIR/lib/libraries