Further fix to the mode where we enter archive recovery after crash recovery.

I missed to returns in the middle of ReadRecord function in my previous fix.
If a WAL file was not found at all during crash recovery, XLogPageRead would
return 'false', and ReadRecord would return without entering archive recovery.

9.2 only. In master, the code is structured differently and does not have this
problem.

Kyotaro HORIGUCHI, Mitsumasa KONDO and me.