Enable keystone token caching by OSC

SDK uses python keyring library to enable token caching. Normally this
is requiring a proper desktop (interactive) session, but there are some
backend plugins working in non-interactive mode. Store cache in an
unencrypted file on FS (this is not worse than storing passwords in
plaintext).

Change-Id: I42d698f15db5918443073fff8f27b926126d1d0f
diff --git a/lib/libraries b/lib/libraries
index 9ea3230..146434e 100755
--- a/lib/libraries
+++ b/lib/libraries
@@ -138,6 +138,10 @@
     # doesn't pull in etcd3.
     pip_install etcd3
     pip_install etcd3gw
+
+    # Add libraries required for token caching by OpenStackSDK/CLI
+    pip_install keyring
+    pip_install keyrings.alt
 }
 
 # Restore xtrace