Fixed minor cppcheck issues:

Do not assign a value to rv, because this value is never used.
Instead declare and assign a value to bool rv in the same line.

Do not assign false to Bool readonly, because this value is never used.
Instead declare the variable and assign a value in the same line.

Other minor problems:

Fixed some guaruntee->guarantee typos in comments.
Fixed copyright headers still referring to the old .c files.
Fixed wrong names in copyright headers.

(LP: #1134251). Fixes: https://bugs.launchpad.net/bugs/1134251.

Approved by Sam Spilsbury.