Summary: Add function to reinitialize a transaction object so that it can be reused. This is an optimization so users can potentially avoid reallocating transaction objects.
Test Plan: added tests
Reviewers: yhchiang, kradhakrishnan, IslamAbdelRahman, sdong
Reviewed By: sdong
Subscribers: jkedgar, dhruba, leveldb
Differential Revision: https://reviews.facebook.net/D53835
5ea9aa3c14