Chromium Updater fix updater self install script

For macOS, when the updater self updates, it uses the .install.sh
script, and this CL should fix a bug in running the script properly.

Change-Id: Ib745fbb3e998fc864ab61a8f9aba99f432c6e757
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2441007Reviewed-by: Joshua Pawlicki <waffles@chromium.org>
Commit-Queue: Michael Chang <donchan@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#812134}

chrome/updater/mac/setup/.install.sh

@@ -30,9 +30,7 @@ main() {
 "${update_dmg_mount_point}/${APP_DIR}/Contents/MacOS/${PRODUCT_NAME}"
 
   # Run the executable with install
-  exit_code="$(${path_to_executable} --install)"
-
-  return exit_code
+  "${path_to_executable}" --install
 }
 
 # Check "less than" instead of "not equal to" in case there are changes to pass