Deal with deleted users before logind restart

lsusers.py

@@ -36,6 +36,7 @@ def get_users_list():
 
 
 def get_resources_percent(username=None):
+    try:
         if username is None:
             user_opt = ['-e']
         else:
@@ -46,6 +47,8 @@ def get_resources_percent(username=None):
         cmd = Popen(['ps', '-o', 'pmem', '--no-headers'] + user_opt, stdin=PIPE, stdout=PIPE, stderr=STDOUT)
         output = map(float, cmd.stdout.read().decode('utf8').split())
         mem_percent = sum(output)
+    except:
+        cpu_percent = mem_percent = 0
     return cpu_percent, mem_percent