Setting a default 'is_rr_approved' value for land command outside try block.
Review Request #8404 — Created Sept. 17, 2016 and discarded
Currently, 'is_rr_approved' may not be set during execution of RBTools' land command
if an Exception other than AttributeError is encountered.This change introduces default values to `is_rr_approved` and `approval_failure` before
attempting to retrieve information from the review request. In the event an exception is
encountered, RBTools will fail gracefully without disclosing a stack trace.Bug ticket: https://hellosplat.com/s/beanbag/tickets/4024/
Testing Done: Ran the land command a few times and observed its functionality.
