Fix another UnicodeDecodeError in bridgedb.persistent log call.

 * CHANGE patch for the same error in previous commit to use
   twisted.python.reflect.safe_repr for better clarity.
 * See https://travis-ci.org/isislovecruft/bridgedb/builds/18503773#L1483
Merge branch 'hotfix/ude-persistent' into testing/tpo-sysrqb/bug9264_rebased_1