Make sure we properly reset an sqlite statement in the upgrade code to avoid
an sqlite assertion which hides the actual error.

* subversion/libsvn_wc/upgrade.c
  (bump_30_upgrade_one_conflict): New function, extracted from...
  (bump_to_30): ... this function. Properly handle errors from
    bump_30_upgrade_one_conflict.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1439802 13f79535-47bb-0310-9956-ffa450edef68