Changes

Revert "hnb_persistent: Use incrementing counter for rate_ctr + stat_item index"

This reverts commit 61e278a452bf4fd240e45f1fe8c094a4b3795317 as it
created errors in our test suite.  Let's live with the cosmetic error
message but have working tests instead.  We should probably consider
removing the printing of the message from libosmocore, at least in case
the counters also have names set?

Closes: OS#6557
Change-Id: I2f7d3f3c88775e2926661e4760ec1d8723c0400c