seq_range_array_remove_range(): Don't break if seq2 is -1U.
seq_range_array_remove_range(): Don't break if seq2 is -1U.

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branch : HEAD

jwm/dovecot-notmuch,jkerihuel/dovecot,jkerihuel/dovecot,jwm/dovecot-notmuch,jkerihuel/dovecot,jwm/dovecot-notmuch,jkerihuel/dovecot,jkerihuel/dovecot,jwm/dovecot-notmuch,jwm/dovecot-notmuch