CRM-15500 fix - Scheduled reminders: if 'Also include' and 'Choose recipients' is selected, and no recipients are entered - reminder is sent to all contacts

https://issues.civicrm.org/jira/browse/CRM-15500
Merge pull request #4471 from monishdeb/CRM-15500

CRM-15500 fix - Scheduled reminders: if 'Also include' and 'Choose recip...