Add extlookup2hiera manpages to redhat and debian packages

Now that a manpage exists for extlookup2hiera, it needs to be part of the
redhat and debian packaging so it can be laid down correctly for those
packages. This commit adds the manpage to the puppet package on redhat and the
puppet-common package on debian.
Merge pull request #1432 from haus/maint/3.1.x/add_extlookup2hiera_manpages

Add extlookup2hiera manpages to redhat and debian packages