install-build-deps: fix missing OR in --check-only

Found a bug in the --check-only logic. Due to a missing OR
a --check-only --ui would ignore non-UI deps.

Change-Id: Ie45ba0987cd9669678d731bed2f8a8586be53820
diff --git a/tools/install-build-deps b/tools/install-build-deps
index a37d87b..df3be2a 100755
--- a/tools/install-build-deps
+++ b/tools/install-build-deps
@@ -565,7 +565,7 @@
   if args.ui:
     # Needs to happen after nodejs is installed above.
     if args.check_only:
-      deps_updated = not CheckNodeModules()
+      deps_updated |= not CheckNodeModules()
     else:
       InstallNodeModules(force_clean=nodejs_updated)