db: remove idle_timeout

... because it was deprecated during Train cycle[1] in favor of the new
connection_recycle_time parameter.

[1] 3eb0e70947

Change-Id: Iecd45f2e551eb46d3d8b839e5911898591272705

manifests/db.pp

@@ -109,10 +109,6 @@
 #
 # DEPRECATED PARAMETERS
 #
-# [*idle_timeout*]
-#   (Optional) Timeout before idle SQL connections are reaped.
-#   Defaults to undef
-#
 # [*min_pool_size*]
 #   (Optional) Minimum number of SQL connections to keep open in a pool.
 #   Defaults to undef
@@ -146,7 +142,6 @@ define oslo::db(
   $db_max_retries          = $::os_service_default,
   $mysql_enable_ndb        = $::os_service_default,
   # DEPRCATED PARAMETERS
-  $idle_timeout            = undef,
   $min_pool_size           = undef,
   $use_tpool               = undef,
 ) {
@@ -194,10 +189,6 @@ define oslo::db(
     }
   }
 
-  if $idle_timeout != undef {
-    warning('The idle_timeout parameter is deprecated. Please use connection_recycle_time instead.')
-  }
-
   if $min_pool_size {
     warning('The min_pool_size parameter is deprecated, and will be removed in a future release.')
   }

releasenotes/notes/remove-db-idel_timeout-ce2e23c94ddc58ea.yaml

@@ -0,0 +1,4 @@
+---
+upgrade:
+  - |
+    The ``oslo::db::idel_timeout`` parameter has been removed.