yum: improve disk usage when update_cache used (#21098)

* Marks metadata files as outdated

Eliminates time records of the metadata and mirrorlists download
for each repository. This forces yum to revalidate the cache for
each repository the next time it is used.

* Command arguments in two separate strings to be compatible if run_command implementation changes. Doc explains a little better what is that parameter doing

lib/ansible/modules/packaging/os/yum.py

@@ -96,13 +96,13 @@ options:
 
   update_cache:
     description:
-      - Force updating the cache. Has an effect only if state is I(present)
-        or I(latest).
+      - Force yum to check if cache is out of date and redownload if needed.
+        Has an effect only if state is I(present) or I(latest).
     required: false
     version_added: "1.9"
     default: "no"
     choices: ["yes", "no"]
-    aliases: []
+    aliases: [ "expire-cache" ]
 
   validate_certs:
     description:
@@ -1081,7 +1081,7 @@ def ensure(module, state, pkgs, conf_file, enablerepo, disablerepo,
     if state in ['installed', 'present', 'latest']:
 
         if module.params.get('update_cache'):
-            module.run_command(yum_basecmd + ['makecache'])
+            module.run_command(yum_basecmd + ['clean', 'expire-cache'])
 
         my = yum_base(conf_file, installroot)
         try:
@@ -1145,7 +1145,7 @@ def main():
             list=dict(),
             conf_file=dict(default=None),
             disable_gpg_check=dict(required=False, default="no", type='bool'),
-            update_cache=dict(required=False, default="no", type='bool'),
+            update_cache=dict(required=False, default="no", aliases=['expire-cache'], type='bool'),
             validate_certs=dict(required=False, default="yes", type='bool'),
             installroot=dict(required=False, default="/", type='str'),
             # this should not be needed, but exists as a failsafe