Recoll crash during xapian commit

Hi,

I have a report of a recollindex crash during a Xapian commit. Of couse
this could be due to previous memory corruption in the Recoll code, but
there is a stack trace going into Xapian code, so I'm posting this in case
this can evoke an idea: https://framagit.org/medoc92/recoll/-/issues/348

The index has been reset at the start of indexing, so this can't be old
file corruption.

Cheers,

jf