perl 5.12.2 does not use /usr/share/perl path, and all that stuff goes
in /usr/lib/perl. This commit fixes cpan class which depends on
/usr/share/perl.
cpan.base/build.bbclass: change /usr/lib/perl5 to /usr/lib/perl
Signed-off-by: Nitin A Kamble <nitin.a.kamble@intel.com>