ssh mixup. Wrong host key. whowto correct.

I took former pc and turned into mythtv-box. I get following error when I try to ssh-remote connect to the mythbox and I dont know howto correct the "known_host-file", see below.:

gunnar@gt-kjallari:~$ ssh gunnar@192.168.1.100
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the RSA host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
29:20:8c:aa:d4:30:fd:16:24:e3:b1:c8:32:c8:2a:e2.
Please contact your system administrator.
Add correct host key in /home/gunnar/.ssh/known_hosts to get rid of this message.
Offending key in /home/gunnar/.ssh/known_hosts:2
RSA host key for 192.168.1.100 has changed and you have requested strict checking.
Host key verification failed.

Known_host-file.:
|1|le/bI0cCTb7j2oKk+//FBLazOxA=|DyaBGWz22wEMVcJXNPzmidgKqnA= ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAmNE4SNp17g4QcHIDyaIm+a58HHRNk4R4F6HdbxuGpseSAlh4t9fYpaqY2lWPUM8b3H9x5efKg/pH0U3Cf6jmc0gHDADoB+4t7eQQXZqWgnsBBAE4pqRk+F7S9yX2W/0RVyKCmZ6zhsUFR1U26ZiSxUdht8PwslQfz1eiYmlPypJ9LJu22L6bjEufNUp4xCzpmFyEWKmRgxaJyz4N4YESEMVg8srGgKjmF56ikO/3BypLIBb6f7uzR+lSKiKektwoWGQpRS0M0xk925UxRok/AlsT6SA9Dsv3XR/cwg2iOozdM3jESPywYgUDyg7DUuKTjm7AOZmVzS1tWLO4cnadww==
|1|YUruLDokqonCNc1KGm4D+rsQA1M=|6R7OeACVtnNRaBNGbppFYNlQkpQ= ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAmNE4SNp17g4QcHIDyaIm+a58HHRNk4R4F6HdbxuGpseSAlh4t9fYpaqY2lWPUM8b3H9x5efKg/pH0U3Cf6jmc0gHDADoB+4t7eQQXZqWgnsBBAE4pqRk+F7S9yX2W/0RVyKCmZ6zhsUFR1U26ZiSxUdht8PwslQfz1eiYmlPypJ9LJu22L6bjEufNUp4xCzpmFyEWKmRgxaJyz4N4YESEMVg8srGgKjmF56ikO/3BypLIBb6f7uzR+lSKiKektwoWGQpRS0M0xk925UxRok/AlsT6SA9Dsv3XR/cwg2iOozdM3jESPywYgUDyg7DUuKTjm7AOZmVzS1tWLO4cnadww==