fix ntp nina demo

Author: Neradoc

ntp_simple_demo/ntp_demo_nina.py

@@ -40,14 +40,16 @@
 
 def try_set_time(esp, tz_offset=0):
     # get_time will raise ValueError if the time isn't available yet.
-    now = None
     try:
-        now_utc = time.localtime(esp.get_time()[0] + tz_offset)
+        now = time.localtime(esp.get_time()[0] + tz_offset)
     except OSError:
         return False
     rtc.RTC().datetime = now
     return True
 
+while not try_set_time(esp, TZ_OFFSET):
+    time.sleep(0.01)
+
 #######################################################################
 # Set the time, waiting until it's available
 #######################################################################