A better way of constructing file names.

[tingyuz]

in the line of init.go -

cf.caKeyFile = filepath.Join(cf.pkiCaDir, cf.caName+skFileExt)

directly combining the strings like this is not very maintainable because it requires that the . between the basename and the extension be in either the file extension variable or the basename, neither of which really makes sense. I think it's better to not have the . in either of these and instead just do cf.caName + "." + skFileExt