Fixed fast poll warning

app/src/main/java/eu/faircode/email/FragmentOptionsSynchronize.java

@@ -199,7 +199,7 @@ public class FragmentOptionsSynchronize extends FragmentBase implements SharedPr
                 if (value != current) {
                     adapterView.setTag(value);
                     prefs.edit().putInt("poll_interval", value).apply();
-                    tvPollBattery.setVisibility(value < 15 ? View.VISIBLE : View.GONE);
+                    tvPollBattery.setVisibility(value > 0 && value < 15 ? View.VISIBLE : View.GONE);
                     grpExempted.setVisibility(value == 0 ? View.GONE : View.VISIBLE);
                 }
             }
@@ -461,7 +461,7 @@ public class FragmentOptionsSynchronize extends FragmentBase implements SharedPr
                 break;
             }
 
-        tvPollBattery.setVisibility(pollInterval < 15 ? View.VISIBLE : View.GONE);
+        tvPollBattery.setVisibility(pollInterval > 0 && pollInterval < 15 ? View.VISIBLE : View.GONE);
         grpExempted.setVisibility(pollInterval == 0 ? View.GONE : View.VISIBLE);
 
         swSchedule.setChecked(prefs.getBoolean("schedule", false) && pro);