The bug we experienced here was that if you loaded the page in a
narrowed view, and then un-narrowed before the first block of messages
for the home view arrived via load_old_messages, then
narrow.deactivate() would re-select ID -1 in home_msg_list. This ends
up calling recenter_view() on the message, which in turn tries to
access the message with message id -1, which fails.
We do sometimes re-select a message ID in order to recenter the view
properly when we prepend messages to a message list, so we can't make
this always a nop; instead we add a check for id -1 in the
message_selected.zephyr event handler.
(imported from commit 66f84a586e59d99aaf0e4ba2cda9fe597b033145)
1cf2d993a6