[perl5-dbi/dbi] deacbb: Cleaned up PERL_VERSION #if's

[H.Merijn Brand]

  Branch: refs/heads/master
  Home:   https://github.com/perl5-dbi/dbi
  Commit: deacbb28b81f196298c0d3f1e82ca7cb257963ae
      
https://github.com/perl5-dbi/dbi/commit/deacbb28b81f196298c0d3f1e82ca7cb257963ae
  Author: H.Merijn Brand - Tux <t...@freedom.nl>
  Date:   2020-07-21 (Tue, 21 Jul 2020)

  Changed paths:
    M DBI.xs
    M dbipport.h

  Log Message:
  -----------
  Cleaned up PERL_VERSION #if's

Also guard with PERL_REVISION == 5