Add local.arch to config introspection

test/conftest.py

@@ -126,6 +126,7 @@ def supported_configs():
     This list should be updated every time yadm learns a new config.
     """
     return [
+        'local.arch',
         'local.class',
         'local.hostname',
         'local.os',

yadm

@@ -1247,6 +1247,7 @@ EOF
 function introspect_configs() {
   local msg
   read -r -d '' msg <<-EOF
+local.arch
 local.class
 local.hostname
 local.os