Remove heat::db from all the components of the module.

This patch is needed to completely remove any require heat::db that
point to heat::db that was removed in change:
I4584cdb12d1f9e624228e6ee34b4bcfbf649a12e

The patch is connected to the fact that in the cited change we
missed those references.

Change-Id: Idd9dcefd52c63e9c8cd74fc39bc4b7ba04f981bc

manifests/api.pp

@@ -32,8 +32,7 @@ class heat::api (
     hasstatus  => true,
     hasrestart => true,
     require    => [Package['heat-common'],
-    Package['heat-api'],
-    Class['heat::db']],
+                  Package['heat-api']],
   }
 
   heat_config {

manifests/api_cfn.pp

@@ -32,7 +32,6 @@ class heat::api_cfn (
     enable     => $enabled,
     hasstatus  => true,
     hasrestart => true,
-    require    => Class['heat::db'],
   }
 
   heat_config {

manifests/api_cloudwatch.pp

@@ -32,7 +32,6 @@ class heat::api_cloudwatch (
     enable     => $enabled,
     hasstatus  => true,
     hasrestart => true,
-    require    => Class['heat::db'],
   }
 
   heat_config {

manifests/engine.pp

@@ -34,8 +34,7 @@ class heat::engine (
     require    => [ File['/etc/heat/heat.conf'],
                     Exec['heat-encryption-key-replacement'],
                     Package['heat-common'],
-        Package['heat-engine'],
-        Class['heat::db']],
+                    Package['heat-engine']],
   }
 
   exec {'heat-encryption-key-replacement':