roomservice: Update branch to arcadia

Change-Id: Icc2fe17c6247efa557ef00aa2cf02e2a97a35df9
diff --git a/build/tools/roomservice.py b/build/tools/roomservice.py
index 5ac9a1a..bee4958 100755
--- a/build/tools/roomservice.py
+++ b/build/tools/roomservice.py
@@ -38,7 +38,7 @@
 # set this to the default remote to use in repo
 default_rem = "github"
 # set this to the default revision to use (branch/tag name)
-default_rev = "s"
+default_rev = "arcadia"
 # set this to the remote that you use for projects from your team repos
 # example fetch="https://github.com/BlissRoms-Devices"
 default_team_rem = "github"