[stable/osclass] Remove distro tag (#8545)

Signed-off-by: Carlos Rodriguez Hernandez <crhernandez@bitnami.com>

stable/osclass/Chart.yaml

@@ -1,5 +1,5 @@
 name: osclass
-version: 3.1.0
+version: 3.1.1
 appVersion: 3.7.4
 description: Osclass is a php script that allows you to quickly create and manage
   your own free classifieds site.

stable/osclass/values.yaml

@@ -10,7 +10,7 @@
 image:
   registry: docker.io
   repository: bitnami/osclass
-  tag: 3.7.4-debian-9
+  tag: 3.7.4
   ## Specify a imagePullPolicy
   ## Defaults to 'Always' if image tag is 'latest', else set to 'IfNotPresent'
   ## ref: http://kubernetes.io/docs/user-guide/images/#pre-pulling-images