revlog: use a `reading` context in `_enforceinlinesize`
We are about to enforce reading context on various operation, so we make sure
top level method are in the right context.
In the future we might move the responsibility of opening the revlog for reading
higher in the call chain but lets limit the disruption for now.
#require serve
$ hg clone http://localhost:$HGPORT/ copy
abort: * (glob)
[100]
$ test -d copy
[1]
$ "$PYTHON" "$TESTDIR/dumbhttp.py" -p $HGPORT --pid dumb.pid
$ cat dumb.pid >> $DAEMON_PIDS
$ hg clone http://localhost:$HGPORT/foo copy2
abort: HTTP Error 404: * (glob)
[100]
$ killdaemons.py