Improve linear histogram limit, and improve error message.
Improve linear histogram limit, and improve error message.

tuxology/bcc,tuxology/bcc,mcaleavya/bcc,brendangregg/bcc,iovisor/bcc,shodoco/bcc,romain-intel/bcc,mkacik/bcc,romain-intel/bcc,shodoco/bcc,iovisor/bcc,brendangregg/bcc,iovisor/bcc,brendangregg/bcc,brendangregg/bcc,mcaleavya/bcc,mcaleavya/bcc,shodoco/bcc,shodoco/bcc,mcaleavya/bcc,tuxology/bcc,iovisor/bcc,shodoco/bcc,mkacik/bcc,romain-intel/bcc,mcaleavya/bcc,mkacik/bcc,iovisor/bcc,tuxology/bcc,brendangregg/bcc,tuxology/bcc,mkacik/bcc,romain-intel/bcc,mkacik/bcc,romain-intel/bcc