Replace copy.deepcopy by manual copy in rolodex.py.

Summary:
This fixes a breakage caused by creating a new Contact object from an old one
via deepcopy() and subsequently committing both to the database. Sqlalchemy
will fail with the error message "A conflicting state was already present in
the identity map."

On the topic of logspam, you may still see warnings of the following form when
syncing new contacts:

  /usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py:1824:
  SAWarning: Attribute history events accumulated on 1 previously clean
  instances within inner-flush event handlers have been reset, and will not
  result in database updates. Consider using set_committed_value() within
  inner-flush event handlers to avoid this warning.

These seem to occur even with the original version of rolodex.py. It appears to
be related to session versioning; working on a fix.

Test Plan: Added some google contacts and ran ./inbox debug.

Reviewers: mg

Reviewed By: mg

Differential Revision: https://review.inboxapp.com/D19