[v2,1/2] cli: panic when failed to allocate memory for the history buffer

[hanyuan]

Hi Tom,

Sorry for disturbing again and again. I have sent three v2 patches in
total to the patchwork, they are:

[v2,1/2] cli: panic when failed to allocate memory for the history buffer
[v2,2/2] cli: allow users to determine history buffer allocation method
[v2,1/1] cli: compile history code if and only if history config is selected	

I made their change logs very complex and their relations are hard to
understand. Please ignore all v2 patches and allow me to resend v3
version series, thanks!

Regards,
Hanyuan