script: use subprocess returncode

Change-Id: Ia1953f389584a372ce2e8255fe19aa7553b54bbf

scripts/build-windows.py

@@ -8,10 +8,8 @@ this_dir = os.path.dirname(os.path.realpath(__file__))
 
 def execute_cmd(cmd, with_shell=False):
     p = subprocess.Popen(cmd, shell=with_shell)
-    _, perr = p.communicate()
-    if perr:
-        return 1
-    return 0
+    _, _ = p.communicate()
+    return p.returncode
 
 
 def build_daemon(parsed_args):