cgeo: Duplicated GSAK logs on GPX import

A user contacted us, that he has a specific problems since some releases (probably starting with 2021.01.10):

• The user handles his caches with GSAK
• Then he exports the desired caches from GSAK into a GPX which he imports to c:geo. This usually also contains caches already stored (from the last import) to refresh them.
• The GSAK GPX contains a special log (as first log) which contains user specific information (selectable by the user)

In former versions this worked perfectly fine (first log is the GSAK special log). Recently he has the problem, that this special log entry gets duplicated on each new import of a GPX with this special log.

The log part of the GPX looks like this (whole file available upon request):

 <groundspeak:logs>
    <groundspeak:log id="-3">
    <groundspeak:date>2021-02-15T08:00:00Z</groundspeak:date>
    <groundspeak:type>Write note</groundspeak:type>
    <groundspeak:finder id="0">GSAK</groundspeak:finder>
    <groundspeak:text encoded="False">Guilford County,  N
    </groundspeak:text>
   </groundspeak:log>

IMHO this is related to the recently introduced merge capability on GPX import but should/could be avoided.