CRM-13937 fix - Lifetime memberships created with a start date older than 3 months ago have a status of expired.

http://issues.civicrm.org/jira/browse/CRM-13937
Merge pull request #2233 from monishdeb/CRM-13937

CRM-13937 fix - Lifetime memberships created with a start date older than 3 months ago have a status of expired.