Bump stemcell to 3146 and set version to 1.6.4 final [#109303310]

Signed-off-by: Felix Reyn <freyn@pivotal.io>

Author: aramprice

example-product/content_migrations/example-product.yml

@@ -1,7 +1,7 @@
 ---
 product: example-product
 installation_schema_version: "1.6"
-to_version: &to_version "1.6.4.0-alpha"
+to_version: &to_version "1.6.4.0"
 
 migrations:
   - from_version: "1.4.0.0"

example-product/metadata/example-product.yml

@@ -1,14 +1,14 @@
 ---
 name: example-product
-product_version: "1.6.4.0-alpha"
+product_version: "1.6.4.0"
 metadata_version: "1.6"
 label: 'Ops Manager: Example Product'
 description: An example product to demonstrate Ops Manager product-author features
 rank: 1
 stemcell_criteria:
   os: ubuntu-trusty
   requires_cpi: false
-  version: "3144" # Bosh stemcell should match Ops Manager with same version
+  version: "3146" # Bosh stemcell should match Ops Manager with same version
 releases:
   - name: example-release
     file: example-release-10.tgz