0019271: Update validation routines with proper lengths

Migrated from: https://tracker.clearos.com/view.php?id=19271

Reported by: PBaldwin

The maximum length of a Certificate Manager's "Unit" is 64 (bytes?). If the user goes over this limit, the following error is thrown:

string too long:a_mbstr.c:XYZ:maxsize=64

Review the validation routines for the certificate parameters.