Refactor electron to always pipe stdout to /dev/null

lib/gui/electron.py

@@ -11,19 +11,22 @@ app_process = None
 def open_url(url):
     global app
 
-    # Any output on stdout will crash inkscape.
-    null = open(os.devnull, 'w')
+    command = []
+    cwd = None
 
     if getattr(sys, 'frozen', None) is not None:
         electron_path = os.path.join(get_bundled_dir("electron"), "inkstitch-gui")
 
         if sys.platform == "darwin":
             electron_path += ".app/Contents/MacOS/inkstitch-gui"
-            subprocess.Popen(["open", "-a", electron_path, "--args", url], stdout=null)
+            command = ["open", "-a", electron_path, "--args", url]
         else:
-            app_process = subprocess.Popen([electron_path, url])
+            command = [electron_path, url]
     else:
         # if we're not running in a pyinstaller bundle, run electron directly
-        app_process = subprocess.Popen(["yarn", "dev", url], cwd=get_bundled_dir("electron"), stdout=null)
+        command = ["yarn", "dev", url]
+        cwd = get_bundled_dir("electron")
 
-    return app_process
+    # Any output on stdout will crash inkscape.
+    null = open(os.devnull, 'w')
+    return subprocess.Popen(command, cwd=cwd, stdout=null)