Merge ~lgp171188/launchpad:add-internal-branch-by-id-root-codehosting-charm into launchpad:master

[Guruprasad]

charm/launchpad-codehosting: Add 'internal_branch_by_id_root' config option

[Colin Watson (cjwatson)]

review: Approve

diff --git a/charm/launchpad-codehosting/config.yaml b/charm/launchpad-codehosting/config.yaml
index 11e39a8..152b0be 100644
--- a/charm/launchpad-codehosting/config.yaml
+++ b/charm/launchpad-codehosting/config.yaml
@@ -77,6 +77,12 @@ options:
       - "# Increased to 2 hours as per https://portal.admin.canonical.com/C47161"
       - timeout client 7200000
       - timeout server 7200000
+  internal_branch_by_id_root:
+    type: string
+    description: |
+      The URL prefix for where branches are served by URLs based on the
+      branch ID.
+    default:
   internal_codebrowse_root:
     type: string
     description: |