Find and fix "no tape block movement" log message regression

As shown in https://gitlab.cern.ch/cta/operations/-/issues/1005, we were getting a large number of No tape block movement for too long error messages after release 4.8.5-1.

This seems to have been a regression.

In the meanwhile, @vyurchen has changed the severity of these messages from ERROR to WARNING (#325 (closed)), but we still need to find what is causing these messages and fix it...