Rewrite killing of xprop

bumblebee/modules/caffeine.py

@@ -67,13 +67,17 @@ class Module(bumblebee.engine.Module):
         return True
 
     def _resume_screensaver(self):
+        pids = []
+        success = True
         for process in psutil.process_iter():
             if process.cmdline() == [bumblebee.util.which('xprop'), '-id', str(self._xid), '-spy']:
-                try:
-                    os.kill(process.pid, 9)
-                except OSError:
-                    return False
-        return True
+                pids.append(process.pid)
+        for pid in pids:
+            try:
+                os.kill(process.pid, 9)
+            except OSError:
+                success = False
+        return success
 
     def state(self, _):
         if self._active: