[Astro Binding] fix NPE in case it's not really dark at night

[sjsf]

fixes #3460
Signed-off-by: Simon Kaufmann simon.kfm@googlemail.com

[FrankR59]

I installed the latest binding (openHAB 2.1.0~20170520012220-1 (Build #922)) but NPEs thrown by astro binding got even worse. There are NPe for almost every astro thing I created:

2017-05-21 12:20:41.937 [ERROR] [.core.internal.folder.FolderObserver] - Error handling update of file '/etc/openhab2/things/astro.things': null. 2017-05-21 12:20:44.801 [ERROR] [org.quartz.core.JobRunShell ] - Job astro:sun:minus15.job-daily-startup-sun threw an unhandled Exception: 2017-05-21 12:20:44.809 [ERROR] [org.quartz.core.ErrorLogger ] - Job (astro:sun:minus15.job-daily-startup-sun threw an exception. 2017-05-21 12:20:44.806 [ERROR] [org.quartz.core.JobRunShell ] - Job astro:sun:home.job-daily-startup-sun threw an unhandled Exception: 2017-05-21 12:20:44.826 [ERROR] [org.quartz.core.ErrorLogger ] - Job (astro:sun:home.job-daily-startup-sun threw an exception. 2017-05-21 12:20:44.894 [ERROR] [org.quartz.core.JobRunShell ] - Job astro:sun:minus45.job-daily-startup-sun threw an unhandled Exception: 2017-05-21 12:20:44.913 [ERROR] [org.quartz.core.ErrorLogger ] - Job (astro:sun:minus45.job-daily-startup-sun threw an exception. 2017-05-21 12:20:45.006 [ERROR] [org.quartz.core.JobRunShell ] - Job astro:sun:minus60.job-daily-startup-sun threw an unhandled Exception: 2017-05-21 12:20:45.008 [ERROR] [org.quartz.core.JobRunShell ] - Job astro:sun:minus30.job-daily-startup-sun threw an unhandled Exception: 2017-05-21 12:20:45.013 [ERROR] [org.quartz.core.ErrorLogger ] - Job (astro:sun:minus60.job-daily-startup-sun threw an exception. 2017-05-21 12:20:45.014 [ERROR] [org.quartz.core.ErrorLogger ] - Job (astro:sun:minus30.job-daily-startup-sun threw an exception. 2017-05-21 12:20:45.070 [ERROR] [org.quartz.core.JobRunShell ] - Job astro:sun:plus15.job-daily-startup-sun threw an unhandled Exception: 2017-05-21 12:20:45.072 [ERROR] [org.quartz.core.JobRunShell ] - Job astro:sun:plus30.job-daily-startup-sun threw an unhandled Exception: 2017-05-21 12:20:45.077 [ERROR] [org.quartz.core.ErrorLogger ] - Job (astro:sun:plus15.job-daily-startup-sun threw an exception. 2017-05-21 12:20:45.077 [ERROR] [org.quartz.core.ErrorLogger ] - Job (astro:sun:plus30.job-daily-startup-sun threw an exception. 2017-05-21 12:20:45.109 [ERROR] [org.quartz.core.JobRunShell ] - Job astro:sun:plus60.job-daily-startup-sun threw an unhandled Exception: 2017-05-21 12:20:45.109 [ERROR] [org.quartz.core.JobRunShell ] - Job astro:sun:plus45.job-daily-startup-sun threw an unhandled Exception: 2017-05-21 12:20:45.111 [ERROR] [org.quartz.core.ErrorLogger ] - Job (astro:sun:plus60.job-daily-startup-sun threw an exception. 2017-05-21 12:20:45.114 [ERROR] [org.quartz.core.ErrorLogger ] - Job (astro:sun:plus45.job-daily-startup-sun threw an exception.

[sjsf]

see #3460 (comment)