Fixes automatic testing of TaskChain requests

TaskChain requests JSON template files had CouchURL argument defined. Which
overrides ConfigCacheUrl. This could have possibly worked only on the defined
host which was testbed, but failed with CouchInternalError otherwise.
Merge pull request #4489 from zdenekmaxa/reqmgr2-couchdb-database-consistency-fix

Fixes automatic testing of TaskChain requests