Move db include from ::octavia to ::octavia::api

The database configuration for octavia isn't required by all services so
moving it out of ::octavia and into ::octavia::api.

Closes-Bug: #1632667
Change-Id: I7a782a1378b94ac001419e331a2e48a8559a6565

manifests/api.pp

@@ -37,6 +37,7 @@ class octavia::api (
 
   include ::octavia::deps
   include ::octavia::policy
+  include ::octavia::db
 
   package { 'octavia-api':
     ensure => $package_ensure,

manifests/init.pp

@@ -205,7 +205,6 @@ class octavia (
 
   include ::octavia::deps
   include ::octavia::logging
-  include ::octavia::db
 
   package { 'octavia':
     ensure => $ensure_package,

releasenotes/notes/dont-initialize-db-in-init-85ac6f87576814d6.yaml

@@ -0,0 +1,5 @@
+---
+upgrade:
+  - In previous releases, ::octavia::db was included in ::octavia even though
+    it isn't required by all users of that class. It has been removed from
+    ::octavia and added to ::octavia::api where it is required.

spec/classes/octavia_init_spec.rb

@@ -17,10 +17,6 @@ describe 'octavia' do
         is_expected.to contain_class('octavia::logging')
       end
 
-      it 'contains the db class' do
-        is_expected.to contain_class('octavia::db')
-      end
-
       it 'installs packages' do
         is_expected.to contain_package('octavia').with(
           :name   => platform_params[:octavia_common_package],