Bug introduce in 3.1-1 and 3.1-2 affecting rare scenario during one specific hour in the year

[vincentvanhees]

In commit 3b9e2b7
earlier this year (in between release 3.1-1 and 3.1-2) I made code simplification around line 793 which has broken the functionality to handle the specific scenario of a sleep episode starting before the double DST hour in the autumn and ending inside it.

I will now prepare a PR to undo this change.