Drop redundant lib/oslo

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

[1] 3ed99c0b27122ff00e2d236086ab16b0cc1887c1

Depends-on: https://review.opendev.org/c/openstack/grenade/+/936095
Change-Id: I6a66359c19d0385beafb4c5e57b6ec3cd6d9cc54
diff --git a/lib/libraries b/lib/libraries
index 9ea3230..9d5d655 100755
--- a/lib/libraries
+++ b/lib/libraries
@@ -1,6 +1,6 @@
 #!/bin/bash
 #
-# lib/oslo
+# lib/libraries
 #
 # Functions to install libraries from git
 #