check_xxx_rr functions should only ever use semantic errors

[k0ekk0ek]

A lot of check functions, the function called after parsing an RR in generic notation, use syntax errors. This is incorrect. The generic notation is frequently used to write RRs that do not meet requirements. Use semantic errors instead so that secondary servers that use generic notation to write RRs that are off can read them back in. The syntax itself is correct as it passed the generic parse function.