Add proper error reporting to shared db lock.
Merge remote-tracking branch 'drebs-github/bug/4435_add-proper-error-reporting-to-shared-db-lock' into develop
Use temp dir for server side locks (#4918).
Merge remote-tracking branch 'refs/remotes/drebs/feature/4918_ensure-server-side-locks-use-temporary-directory' into develop
Move lock reource to its own file.
Allow sync of large files (~100MB) (#4836).
Add test for syncing many small documents (#4836).
Make couch tests use only one couch instance.