Update krb5 to 1.12. Security/krb5 tracks MIT KRB5 current release.
Adjust the newly created krb5-maint with a new portname and conflicts.
Krb5-maint is a maintenance release for those who wish to use the previous
release of krb5. krb5-maint remains at 1.11.3.
Adjust CONFLICTS in security/heimdal and security/srp to account for the
newly repocopied krb5-maint.
Adjust security/Makefile to include krb5-maint.