Simplify flatpak detection

onionshare_gui/gui_common.py

@@ -18,7 +18,6 @@ You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 """
 import os
-import json
 
 from onionshare import strings
 from onionshare.onion import Onion
@@ -39,16 +38,7 @@ class GuiCommon:
         self.local_only = local_only
 
         # Are we running in a flatpak package?
-        self.is_flatpak = False
-        if os.path.exists("/app/manifest.json"):
-            try:
-                with open("/app/manifest.json") as f:
-                    manifest_data = json.loads(f.read())
-                    if manifest_data["id"] == "org.onionshare.OnionShare":
-                        self.is_flatpak = True
-                        self.common.log("GuiCommon", "__init__", "is_flatpak=True")
-            except:
-                pass
+        self.is_flatpak = os.path.exists("/.flatpak-info")
 
         # Load settings
         self.common.load_settings()