[perl #95544] Make UNIVERSAL::VERSION return $VERSION

[perl #95544] Make UNIVERSAL::VERSION return $VERSION

With this patch:
$ ./miniperl -le ' $VERSION = "3alpha"; print "main"->VERSION'
3alpha
$ ./miniperl -le ' $VERSION = "3alpha"; print "main"->VERSION(4)'
Invalid version format (non-numeric data) at -e line 1.

See the discussion starting at:
http://www.nntp.perl.org/group/perl.perl5.porters/2011/06/msg173710.html

Basically, this patch allows custom version parsers to call ->VERSION
to retrieve the version, even if the default parser would choke on it.