bugfix: remove off by one in checking the history size
bugfix: remove off by one in checking the history size

It may not be important to have 1000 history entries instead of 1001,
but we should respect the users configuration choices.

hut/vimprobable,DeadDork/vimprobable2,hut/vimprobable,hut/vimprobable,desyncr/vimprobable,fanglingsu/vimprobable,fanglingsu/vimprobable,ThomasAdam/vimprobable,DeadDork/vimprobable2,desyncr/vimprobable,ThomasAdam/vimprobable,fanglingsu/vimprobable,ThomasAdam/vimprobable,DeadDork/vimprobable2,DeadDork/vimprobable2,desyncr/vimprobable,desyncr/vimprobable