CPAN: Fix stripping of perllocal.pod if cpan_perl_lib_path is set
CPAN: Fix stripping of perllocal.pod if cpan_perl_lib_path is set

For example, if cpan_perl_lib_path is set to "/usr/share/perl5", all
packages created with fpm will contain this file:

    /usr/share/perl5/x86_64-linux-gnu-thread-multi/perllocal.pod

The current code only works if cpan_perl_lib_path is undefined.

Also see #443 and #510.

wyaeld/fpm,godp1301/fpm,josephfrazier/fpm,mzaccari/fpm,joseph-onsip/fpm,Tapjoy/fpm,wyaeld/fpm,schatt/fpm,elvido/fpm,Tapjoy/fpm,mzaccari/fpm,paul-krohn/fpm,virtkick/fpm,wyaeld/fpm,elvido/fpm,tjyang/fpm,hlawrenz/fpm,linearregression/fpm,schatt/fpm,sideci-sample/sideci-sample-fpm,linearregression/fpm,godp1301/fpm,elvido/fpm,doghrim/fpm,gearmover/fpm,Tapjoy/fpm,pskrz/fpm,vi4m/fpm,hlawrenz/fpm,gearmover/fpm,pskrz/fpm,snailwalker/fpm,cturra/fpm,doghrim/fpm,fetep/fpm,pskrz/fpm,vi4m/fpm,mzaccari/fpm,snailwalker/fpm,hlawrenz/fpm,fetep/fpm,elvido/fpm,tjyang/fpm,mildred/fpm,paul-krohn/fpm,hlawrenz/fpm,gearmover/fpm,vi4m/fpm,mzaccari/fpm,josephfrazier/fpm,joseph-onsip/fpm,godp1301/fpm,linearregression/fpm,cturra/fpm,pskrz/fpm,sideci-sample/sideci-sample-fpm,mildred/fpm,rbramwell/fpm,vi4m/fpm,virtkick/fpm,linearregression/fpm,rbramwell/fpm,rbramwell/fpm,doghrim/fpm,wyaeld/fpm,joseph-onsip/fpm,doghrim/fpm,schatt/fpm,gearmover/fpm,joseph-onsip/fpm,fetep/fpm,godp1301/fpm,dischord01/fpm,dischord01/fpm,dischord01/fpm,jerizm/fpm,josephfrazier/fpm,fetep/fpm,tjyang/fpm,schatt/fpm,mildred/fpm,josephfrazier/fpm,cturra/fpm,Tapjoy/fpm,tjyang/fpm,snailwalker/fpm,virtkick/fpm,jerizm/fpm,dischord01/fpm,rbramwell/fpm,snailwalker/fpm,jerizm/fpm,sideci-sample/sideci-sample-fpm,cturra/fpm,mildred/fpm,paul-krohn/fpm,virtkick/fpm,paul-krohn/fpm,jerizm/fpm